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A retrospective cohort mortality study of 10,763 Amoco Corporation oil refinery workers employed between 1970 and 1980 showed low overall mortality; the standardized mortality ratio for all causes of death was 73 for white males and 68 for black males. White male mortality was examined by several exposure classifications devised for group cohort members by potential for exposure to refinery processes and exposure to two components of petroleum (light aromatic hydrocarbons and heavy oils). Statistically significant elevations were found in various exposure groups for skin cancers, digestive system cancers, and benign neoplasms. Of these, skin cancer mortality appeared to increase with increasing exposure.

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This paper describes a morbidity data base for epidemiologic studies which uses information from health insurance claims. Strengths of the data base include completeness and relatively low cost. A limitation is the length of time needed for all claims to be received and processed: rates generated using current information are lower than they will be after all claims are processed. Nevertheless, internal comparisons can presently be made using such rates. Examples illustrate differences in claims experience according to employees' smoking habits and according to kind of job.

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This paper describes and compares two methods used to assign exposure categories to 10,766 petroleum refinery employees included in an epidemiological study. The first scheme grouped individuals into six organization (OR) job groups: Administrative, Maintenance, Operations, Laboratory, General and Other. This scheme used "most common administrative department," as determined by computerized job histories. For the second classification scheme, "most common job title" and "most common plant location" were used to group individuals in four ways (IH codes): 1)job type (administrative, maintenance, operations and unknown); 2) contact with refinery processes; 3) exposure to light aromatics; and 4) exposure to heavy oils. Exposure categories for the latter three were none, occasional, routine and unknown. Comparison of the two schemes showed that OR job groups developed from administrative job histories were sometimes useful in classifying employees according to refinery exposures. While OR job groups were acceptable for employees clearly in managerial, maintenance or operations positions, IH codes provided more precise exposure profiles for these three relatively homogeneous groups. For individuals in laboratory positions and those with vague or unspecified department codes (23% of this cohort), the IH classification codes were necessary to group employees by job and exposure.

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Smoking habits of White male employees of a large oil company were analyzed. There were only slight differences in smoking habits between refinery and nonrefinery employees. Salaried employees, both at refineries and elsewhere, smoked much less than hourly employees.

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Experiments with the aerotolerant anaerobe Streptococcus lactis provide the opportunity for determining the proton motive force (Deltap) in dividing cells. The two components of Deltap, DeltaPsi (the transmembrane potential) and DeltapH (the chemical gradient of H(+)), were determined by the accumulation of radiolabeled tetraphenylphosphonium (TPP(+)) and benzoate ions. The DeltaPsi was calibrated with the K(+) diffusion potential in starved, valinomycin-treated cells. With resting, glycolyzing cells, the Deltap was measured also by the accumulation of the non-metabolizable sugar thiomethyl-beta-galactoside (TMG). In resting cells the Deltap, calculated either by adding DeltaPsi and ZDeltapH or from the levels of TMG, was relatively constant between pH 5 to 7, decreasing from 160 to 150 mV and decreasing further to 100 mV at pH 8.0. With the TPP(+) probe for DeltaPsi, we confirmed our previous finding that the K(+) ions dissipate DeltaPsi and increase DeltapH, whereas Na(+) ions have little effect on DeltaPsi and no effect on DeltapH. [(3)H]TPP(+) and [(14)C]benzoate were added during exponential phase to S. lactis cells growing at pH 5 to 7 at 28 degrees C in a defined medium with glucose as energy source. As with resting cells, the DeltapH and DeltaPsi were dependent on the pH of the medium. At pH 5.1, the DeltapH was equivalent to 60 mV (alkaline inside) and decreased to 25 mV at pH 6.8. The DeltaPsi increased from 83 mV (negative inside) at pH 5.1 to 108 mV at pH 6.8. The Deltap, therefore, was fairly constant between pH 5 and 7, decreasing from 143 to 133 mV. The values for Deltap in growing cells, just as in resting cells, are consistent with a system in which the net efflux of H(+) ions is effected by a membrane-bound adenosine triphosphatase and glycolytically generated adenosine triphosphate. The data suggest that in both growing and resting cells the pH of the medium and its K(+) concentration are the two principal factors that determine the relative contribution of DeltapH and DeltaPsi to the proton motive force.

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