Effects of Oral Meloxicam and Topical Lidocaine on Pain associated Behaviors of Piglets Undergoing Surgical Castration.

The objective of this study was to find a practical means of reducing pain associated with surgical castration by evaluating the effects of oral meloxicam and topical lidocaine, separately and in combination, on behavioral indicators of pain in piglets. Two hundred thirty-five piglets were surgically castrated between three and seven days of age. Immediately following castration, piglets received one of four treatments: (1) No pain mitigation (C; control; n = 58); (2) NSAID only (M; meloxicam; n = 59); (3) Topical anesthetic (L; lidocaine spray; n = 60); or (4) NSAID and topical anesthetic (X; meloxicam and lidocaine spray; n = 59). Behaviors were recorded by direct observation of individual piglets using five-minute scan samples over a five-hour period, for three days post-castration. Results of the experiment demonstrate the administration of oral meloxicam and topical lidocaine spray at the time of castration under the current methods did not mitigate pain associated with the procedure (P = 0.09; C: 2.1 ± 0.1, L: 2.4 ± 0.1, M: 2.1 ± 0.1 and X: 2.1 ± 0.1).

Historical Context and Recent Advances in Exposure-Response Estimation for Deriving Occupational Exposure Limits.

Virtually no occupational exposure standards specify the level of risk for the prescribed exposure, and most occupational exposure limits are not based on quantitative risk assessment (QRA) at all. Wider use of QRA could improve understanding of occupational risks while increasing focus on identifying exposure concentrations conferring acceptably low levels of risk to workers. Exposure-response modeling between a defined hazard and the biological response of interest is necessary to provide a quantitative foundation for risk-based occupational exposure limits; and there has been considerable work devoted to establishing reliable methods quantifying the exposure-response relationship including methods of extrapolation below the observed responses. We review several exposure-response modeling methods available for QRA, and demonstrate their utility with simulated data sets.

Mortality at an automotive engine foundry and machining complex.

Mortality was analyzed for an automotive engine foundry and machining complex, with process exposures derived from department assignments. Logistic regression models of mortality odds ratios (ORs) were calculated for 2546 deaths, and numbers of work-related deaths were estimated. Lung cancer mortality in the foundry was increased where cleaning and finishing of castings was performed (OR, 1.7; 95% CI, 1.15 to 2.4 [at mean exposure duration of exposed cases]) and in care-making after 1967 (OR, 1.5; 95% CI, 1.11 to 2.0). Black workers had excess lung cancer mortality in machining heat-treat operations (OR, 2.5, 95% CI, 1.4 to 4.3) and excess nonmalignant respiratory disease mortality in molding (OR, 2.5; 95% CI, 1.16 to 5.5) and core-making (OR, 2.7; 95% CI, 1.25 to 5.8). Stomach cancer mortality was elevated among workers with metalworking fluid exposures in precision grinding (OR, 2.4; 95% CI, 1.14 to 5.1). Heart disease mortality was increased among all workers in molding (OR, 1.6; 95% CI, 1.09 to 2.3), as was stroke mortality among workers exposed to metalworking fluids (OR, 1.8; 95% CI, 1.22 to 2.7). Malignant and nonmalignant liver disease mortality was elevated in assembly/testing and precision grinding. In this modern foundry, 11% of deaths were estimated to be work-related despite it's being largely in regulatory compliance over its 40-year existence. Machining plant exposures accounted for 3% or more of deaths there.

Medical insurance claims and surveillance for occupational disease: analysis of respiratory, cardiac, and cancer outcomes in auto industry tool grinding operations.

To evaluate medical insurance claims for chronic disease investigation, claims from eight automotive machining plants (1984 to 1993) were linked with work histories (1967 to 1993), and associations with respiratory, cardiac, and cancer conditions were investigated, in a case-control design analyzed with logistic regression. The primary focus was tool grinding, but other important processes examined were metal-working, welding, forging, heat treat, engine testing, and diverse-skilled trades work. Considerable variability in claim-derived incidence rates across plants was not explained by age or known exposure differences. Asthma incidence increased in tool grinding (at mean cumulative duration: odds ratio [OR], 3.0; 95% confidence interval [CI], 0.90 to 10.0), as did non-ischemic heart disease (cardiomyopathy, cor pulmonale, rheumatic heart disease, or hypertension; OR, 3.1; 95% CI, 1.26 to 7.6). These trends appeared in models with deficits (OR < 1.0) for those ever exposed to tool grinding because of exposure-response miss-specification, demographic confounding, or removal of high-risk workers from the exposed group. The apparent cancer rates identified from claims greatly exceeded the expected rates from a cancer registry, suggesting that diagnostic, "rule-out," and surveillance functions were contributing. This study supports the epidemiologic use of medical insurance records in surveillance and, possibly, etiologic investigation and identifies issues requiring special attention or resolution.

Protein kinase C inhibitors attenuate protective effect of high glucose against hypoxic injury in H9c2 cardiac cells.

In this study, we demonstrated that PKC inhibitors significantly attenuated the cardioprotective effect produced by high-glucose (22 mM) treatment for 48 h against hypoxic injury in H9c2 cardiac cells. PKC activators mimicked the cardioprotective effect of high glucose. These results suggest a possible role of PKC activation in high-glucose--induced protection.

The healthy worker survivor effect and mortality at two automotive engine manufacturing plants.

Attributes such as time since hire or length of followup may be important in occupational mortality due to the "healthy worker survivor effect." In a regression analysis of mortality odds ratios at two automotive engine plants, strong effects of overall employment duration (latency weighted) were observed in addition to effects for (similarly weighted) cumulative exposures. The duration effects were negative for several cancer and noncancer outcomes, and confounded exposure effects. The lung cancer odds ratio declined to 0.68 (95% CI = 0.51, 0.90) at the mean duration of employment. With control for employment duration, adjusted lung cancer odds ratios for work as millwrights increased from 3.0 to 3.8, and for work in cylinder head production, from 3.3 to 3.9. Several causes of death with strong duration effects were smoking-related, suggesting diminished smoking risk factors with increasing employment duration. Similarly, trends for cirrhosis of the liver mortality suggested the alcohol risk factor is smaller in long-duration workers. If personal risk factors are an important component of the healthy worker survivor effect, they could be powerful negative confounders of exposure-response for related outcomes. Including a term for employment duration in regression models appears to partially correct for healthy worker survivor bias.

A survey of mortality at two automotive engine manufacturing plants.

Mortality at two engine plants was analyzed using proportional mortality and logistic regression models of mortality odds ratios to expand previous observations of increased cancers of the stomach, pancreas, and bladder, and cirrhosis of the liver among workers exposed to machining fluids. Causes of death and work histories were available for 1,870 decendents. There was a significant excess of deaths coded as diabetes for white men in both plants (PMR = 25/16.7 = 1.5, 95% CI = 1.02, 2.20), and a deficit of respiratory diseases. Black men had fewer than expected diabetes deaths and more emphysema deaths. Elevated PMRs for cancers of the stomach, pancreas, prostate, bladder, and kidney were not statistically significant in plantwide populations. However, stomach cancer mortality increased with duration in camshaft and crankshaft production at Plant 1 (OR = 5.1, 95% CI = 1.6, 17; at mean duration of exposed cases), and among tool room workers (OR = 6.3, 95% CI = 1.3, 31), but these results were based on five cases. Nitrosamines were probably present in camshaft and crankshaft grinding at Plant 1. Pancreas cancer risk increased among workers at both plants ever employed in inspection (OR = 2.5, 16), in machining with straight oil (OR = 3.6, 95% CI = 1.04, 12), or in skilled trades (OR = 2.9, 95% CI = 1.1, 7.5). Lung cancer increased in cylinder head machining (OR = 3.9, 95% CI = 1.4, 11), millwright work (OR = 3.8, 95% CI = 1.6, 9.0), and in Plant 2 generally (OR = 1.45, 95% CI = 0.97, 2.2). Potential lung carcinogens included heat treatment emissions, chlorinated oils, and coal tar fumes (millwrights). Bladder cancer increased with duration among workers grinding in straight oil MF (OR = 3.0, 95% CI = 1.15, 7.8) and in machining/heat-treat operations (OR = 2.9, 95% CI = 1.14, 7.2).

Occupational disease surveillance using disability insurance at an automotive stamping and assembly complex.

Sickness and accident-insurance (sick leave) claims at an automotive stamping and assembly complex were analyzed using Poisson regression over a 4-year period to identify occupational health problems. The incidence of lower-respiratory disability (excluding asthma) was higher in painting operations (rate ratio [RR] = 2.9, 95% confidence interval [CI] = 1.2 to 6.8), and final assembly and processing areas (RR = 2.7, 95% CI = 1.0 to 7.4) at the assembly plant, and in metal assembly (welding) areas (RR = 2.8, 95% CI = 1.4 to 5.7) at the stamping plant. Disability rates for upper-extremity musculoskeletal disorders were statistically significantly higher (RR = 3.1 to 3.8) in major assembly plant production areas, as were back disability rates (RR = 1.5). During the first 6 months of new work assignments in painting or final assembly, respiratory problem rates were four times higher than in other areas. Upper-extremity musculoskeletal rate ratios ranged from 4.4 to 5.7 for new assignments in body, hard trim, and chassis areas. Higher rates in new assignments appeared to result from assignment changes precipitated by developing health problems, or from routine assignments to new tasks, some of which conferred high risk and were tolerated for less than 6 months. Musculoskeletal disability was consistent with known ergonomic hazards and paralleled that reported on the Occupational Safety and Health Administration log. Work-related musculoskeletal and other problems can be readily identified from disability insurance claims without dependence on plant medical visits or workers' compensation records. Disability insurance appears to absorb considerable work-related medical and absence costs.

A neurological disease cluster at a manufacturing plant.

A case-control study was conducted an at automotive carburetor plant to investigate exposures associated with a cluster of cases exhibiting neurological symptoms that resembled multiple sclerosis. Eighteen cases were identified with symptom onset between 1970 and 1985. Four controls per case were selected randomly from the plant population, and they were matched by year of birth, gender, and ethnicity. From work histories and telephone interviews, cumulative exposures for 10 chemical or process categories were computed, based on rank estimates of exposure levels. Mantel-Haenszel procedures and logistic regression modeling produced statistically significant relative risks associated with die-casting and organophosphate exposures, using unweighted and latency-weighted cumulative exposures. The study was hampered by the inability to pursue further clinical neurological evaluation of the cases, by the small number of cases, and by uncertainties of exposure assessment. A delayed neuropathy arising from organophosphate exposure in hydraulic and machining fluids is proposed.

Cumulative trauma disorders of the hand and wrist in the auto industry.

Surveillance for cumulative trauma disorders (CTDs) of the hand and wrist was carried out in five US automotive plants from 1985 to 1986, using Occupational Safety and Health Administration (OSHA) Form 200 injury and illness logs and medical insurance claims. Results using both record sources indicated that hand and wrist disorders may be more common in foundries than in other types of automotive plants. Similarly, in assembly plants, employees in certain departments appeared to be at higher risk for CTDs. Although our results are based on small numbers of cases, they suggest plants and departments that might be targeted for more detailed investigation.

Use of medical insurance claims for surveillance of occupational disease. An analysis of cumulative trauma in the auto industry.

Medical insurance claims, linked with work histories for a large automotive manufacturer over a 3-year period, identified large numbers of cases of potentially work-related diseases, including 30,600 episodes of probable cumulative trauma disorders (CTD). CTD incidence rates were calculated within five plants, and high-risk areas identified, however, unknown differences in medical insurance coverage by exposure group limited interpretation. Case-control analyses, with controls also identified by insurance claims, addressed coverage and produced age-adjusted and sex-adjusted estimates of risks. All five plants had departments with statistically significant, elevated risks for one or more of the diagnoses carpal tunnel syndrome, CTD of other upper extremities, rotator cuff syndrome, CTD of the neck and of the lower back. Medical insurance claim data linked with work history provide the basis for practical and comprehensive surveillance for CTD and potentially a variety of other occupational diseases.

A technique for the preparation of cross-sectional TEM samples of ZnSe/GaAs heterostructures which eliminates process-induced defects.

Cross-sectional transmission electron microscopy (TEM) sample preparation of ZnSe/GaAs epitaxial films is investigated. Conventional argon ion milling is shown to produce a high density (approximately 5-8 x 10(11)/cm2) of small (diameter approximately 60-80 A) extended defects (stacking faults, microtwins, double positioning twins, etc.). In addition, transmission electron diffraction results indicate a thin ZnO layer can also occasionally form upon ion milling or electron-beam irradiation although the exact conditions for ZnO formation are not well understood. Conventional TEM (amplitude contrast) and high-resolution TEM (phase contrast) imaging in combination with transmission electron diffraction studies were performed to determine the optimum method of removing the ion milling related damage and ZnO layers during sample preparation. HF/HCl, NaOH/H2O, H2SO4/H2O2/H2O and Br2/CH3OH etching mixtures as well as low voltage argon or iodine ion milling were studied. A low energy (2 keV) iodine or argon ion milling step was shown to remove the ZnO layer and reduced the density of the extended defects associated with Ar+ ion milling, but was unsuccessful in removing all of the defects. Auger electron spectroscopy results indicate residual iodine was either left on the surface or implanted beneath the surface during iodine ion milling. Etching the XTEM samples in HF/HCl was shown to be effective in removing the ZnO layer but had little or no effect on the ion milling induced defects. Etching the samples in a 0.5% Br2/CH3OH solution resulted in complete elimination of the ion milling induced extended defects including the residual defects associated with iodine ion milling. In addition the Br2/CH3OH etch produced the best surface morphology. Thus a brief (1-2 seconds) Br2/CH3OH etch after conventional preparation (argon ion milling) of cross-sectional ZnSe/GaAs TEM samples appears to be an inexpensive and superior alternative to iodine ion milling.

A comparison of PMRs and SMRs as estimators of occupational mortality.

Standardized mortality ratios (SMRs) for occupational diseases are confounded by health differences between industrial and general populations. In 109 industrial cohorts largely free of work-related mortality, these selection effects were sizable for both malignant and nonmalignant outcomes. All-cancer SMRs were considerably less than 1.0 for many cohorts, and lung cancer was subject to almost as much selection-derived confounding as nonmalignant disease. Standardized proportional mortality ratios (PMRs) (approximated by relative SMRs (RSMRs] were less confounded than SMRs in estimating occupational risk. PMRs appeared to overestimate cancer mortality on average by 6%, while SMRs underestimated by 13%. PMRs underestimated nonmalignant respiratory disease by 16 percent but SMRs underestimated by 39 percent. The sources of confounding, in addition to selection on health status at hire, most likely include social class. SMRs, in the absence of internal population comparisons, would fail to detect both malignant and nonmalignant work-related mortality in many industrial cohorts.