Biomedical subjects

M F Hallock

Publications and source records attributed to M F Hallock.

4 recordsLinked to original sources

PubMed1994

Estimation of historical exposures to machining fluids in the automotive industry.

A retrospective exposure assessment study in the automotive parts industry conducted in conjunction with a cancer mortality and respiratory morbidity study [Kennedy et al. (1989): Am J Ind Med 15:627-641; Eisen et al. (1992): Am J Ind Med 22:809-824; Tolbert et al. (1992): Scand J Work Environ Health 18:351-360] describes exposure to different types of machining fluids and selected components that may contribute to the conditions investigated. A dataset of 394 industrial hygiene measurements made between 1958 and 1987 was used to estimate past machining fluid levels using a linear statistical model. The effects of different plants, machining fluid types, machining operations, and time periods were examined in the model. Separate analyses examined the effects of different sampling and analysis methods and other measurement variables. Machining fluid levels prior to 1970 were generally two to five times higher than subsequent measurements. The arithmetic mean exposure of all measurements taken before 1970 was 5.42 mg/m3. Arithmetic means for different subgroups ranged from 0.59 to 20.28 mg/m3, depending upon plant, machining fluid, and operation. The arithmetic mean exposure after 1980 was 1.82 mg/m3 with subgroups ranging from 0.45 to 2.79 mg/m3. Changes in exposure levels generally corresponded with reported changes in plant environments such as installation of enclosures and local exhaust ventilation on machines.

Analysis of Variance↗

PubMed1992

Mortality studies of machining-fluid exposure in the automobile industry. II. Risks associated with specific fluid types.

Excesses of digestive and respiratory cancers have been reported previously in association with exposure to machining fluids, agents in widespread use as coolants and lubricants in machining operations. Previous studies have had limited power to distinguish the effects of the different types of machining fluids in use. In a cohort of over 30,000 workers employed at two automotive plants in Michigan, mortality patterns were studied in relation to exposure to each of the three major fluid types--straight oils, soluble oils, and synthetic fluids. Standardized mortality ratios were estimated for subgroups of the cohort ever exposed to each of the three fluid types, and Poisson regression analyses were used to assess trends in risk with duration of exposure. The data suggest modest positive associations between exposure to straight oils and rectal, laryngeal, and prostatic cancer and a negative association between soluble and synthetic fluid exposure and lung cancer.

Adult↗

PubMed1987

A new technique for collecting ambient diesel particles for bioassays.

This paper describes a new application of a viable aerosol sampler, the Liquid Electrostatic Aerosol Precipitator (LEAP), for the collection of diesel particles for bioassays of pulmonary toxicity and mutagenicity or carcinogenicity. Currently used methods (filtration, dry electrostatic precipitation) cause agglomeration of particles and increases in particle size up to twenty-fold, which may alter particle toxicity significantly. Collection of diesel particles with the LEAP preserved submicronic particle size. Differences in chemical composition of extracts of surface adsorbents as compared to particles collected on filters also were observed. This technique may be applicable for collection of other types of combustion products or oil mists that agglomerate when collected by filtration.

Air Pollutants↗

PubMed1977

Some characteristics of amnesia induced by FLA-63 an inhibitor of dopamine beta hydroxylase.

The amnesic effects of FLA-63, a potent dopamine-beta-hydroxylase (DBH) inhibitor, were investigated in a food motivated spatial discrimination task. Groups of C57BL/6J mice were injected with either 5 mg/kg, 15 mg/kg, 25 mg/kg, 35 mg/kg or physiological saline 4 hr prior to training. Amnesia was observed 24 hr following training at all dose levels except 5 mg/kh. The performance deficit was specific to memory of the discrimination and not the result of state-dependency. Training conditions which produce an increase in habit strength prevented the amnestic effects of FLS-63. Spontaneous recovery of memory occurred 48 hr following drug administration. Recovery from amnesia was also induced by injections of a monoamine oxidase inhibitor, pargyline, administered 2 hr prior to the retention test. These data suggest that amnesia induced by norpinephrine (NE) depletion is the result of impairment of mechanisms necessary for memory retrieval.

Amnesia↗