Assessment of colorectal cancer screening outcomes among workers involved in polypropylene manufacture.

To follow up on a previous finding of an elevated colorectal cancer incidence rate among Exxon employees on a unit devoted to the manufacture of polypropylene (the polyolefin unit [POU]), a company-sponsored screening program was offered to all former and present POU workers. Overall participation was 52.5%, with lower participation among older workers and workers who had retired or were no longer employed by the company. Evaluation of polyp prevalence rates for POU workers v rates for non-Exxon employees screened at the same clinic showed a general pattern of elevated rates for POU employees, especially for mechanical and process workers. This pattern was most marked for polyps at least 0.5 cm in diameter, but findings were less clear for adenomatous polyps. The effect of factors that might bias evaluation of colorectal polyp prevalence rates (eg, selection bias, observation bias, genetic susceptibility) is discussed, but none of these factors seemed a likely explanation for the findings observed in this study.

Factors associated with participation in an occupational program for colorectal cancer screening.

This study reports factors associated with participation in a colorectal cancer screening program for a cohort of workers on a polypropylene manufacturing unit. The impetus for the screening program was the discovery of a colorectal cancer cluster among workers on this unit. The program included a life-style/risk factor questionnaire, fecal occult blood test, a 60-cm colonoscopy, and an air-contrast barium enema. Overall, 52.5% of the 406 men who were offered screening participated in the program. Of those screened, only 40% attended a briefing, but over 80% of those who attended a briefing came for screening. Factors associated with completion of screening are analyzed and discussed in the context of the literature on participation in colorectal screening programs. The implications for colorectal cancer screening of occupational groups believed to be at high risk are considered.

Evaluation of excess colorectal cancer incidence among workers involved in the manufacture of polypropylene.

In response to reports of an unusually high number of colorectal cancers among employees on a unit devoted to the manufacture of polypropylene, we examined colorectal cancer incidence rates for 335 workers with at least 6 months employment on this unit from 1960 to 1985. Assuming a 10-year latent period, we found a significant 5.6-fold colorectal cancer excess (7 observed/1.26 expected, standardized incidence ratio (SIR) = 5.6, 95% confidence interval (CI) 2.2 to 11.5), concentrated among mechanical (5 observed/0.47 expected, SIR = 10.6, 95% CI 3.4 to 24.7) and process workers (2 observed/0.40 expected, SIR = 5.0, 95% CI 0.6 to 17.8). No colorectal cancer was found among administrative/office personnel on our study roster. All of the cancers occurred in employees who initially worked on the unit during its first 6 years of operation, and the minimum interval from start of employment to cancer development was 20 years. In addition, the ages of the cancer cases suggested a younger age distribution than would be expected based on general population rates. Since this study was descriptive in nature, we could not evaluate whether the cancer excess was related to occupational exposures, other environmental factors, or the random clustering of cancers in our worker populations (viz, "chance"). Further studies are currently ongoing to assess occupational and/or personal factors that may be related to this colorectal cancer excess.

The biosynthesis, absorption, and origin of cholesterol and plant sterols in the Florida land crab.

In order to study the biosynthesis, composition, and origin of sterols in the Florida land crabs, Cardisoma guanhumi (Latreille), we fed 17 male crabs either a cholesterol-free or a high cholesterol diet for 2 to 7 weeks. The origin of sterols in these crabs, whether from biosynthesis or from the diet, was determined by tahree procedures: the incorporation of isotopic mevalonate into the cholesterol when the diet was cholesterol-free; the absorption of isotopic cholesterol and sitosterol from the diet; the cholesterol and plant sterol concentrations of hepatopancreas, plasma, and muscle under conditions of cholesterol-free and high cholesterol diets. In addition, the interconversion of cholesterol and sitosterol was investigated. Dietary sterols of plant and animal sources were readily absorbed and provided the major source of sterols for this species of crab. The biosynthesis of cholesterol from mevalonate in this crab was minimal. However, cholesterol was synthesized from dietary sitosterol by dealkylation. Cholesterol and the three plant sterols (24 epsilon-methyl cholesterol, stigmasterol, and sitosterol) were found in the hepatopancreas, plasma, and muscle of the crab. Plant sterols contributed from 9 to 37% of the total sterols in the hepatopancreas, plasma, and muscle of the crabs fed a cholesterol-free diet.

Hyperpyrexia in catatonic states.

A patient with an underlying brain disease and catatonia associated with fever of unknown origin, who responded to ECT is presented. The role of dopamine in the basal ganglia in the etiology of catatonic states and its possible relationship to the symptomatology of the patient and his response to ECT is discussed.