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Biomedical subjects

D Clapp

Publications and source records attributed to D Clapp.

6 recordsLinked to original sources
PubMed1990

Biological monitoring of a worker acutely exposed to MBOCA.

A 30 year-old male polyurethane worker was exposed to an accidental spill of 4,4'-methylene-bis-2-chloroaniline (MBOCA) at a plant producing MBOCA-cured plastic products. Exposure to MBOCA is significant in that this compound is a known animal carcinogen and a suspected human carcinogen. The employee was sprayed over his upper body and extremities with molten MBOCA while cleaning out a clogged hose from a MBOCA and polymer mixing machine. The subsequent environmental and medical evaluation of this episode included serial urinary MBOCA samples from the worker over a 2 week period to allow the calculation of a biological half-life for this compound. This worker experienced a very high dose of MBOCA as judged by his urinary MBOCA levels (peak value of 1,700 ppb 4 hours after exposure). There were no acute symptoms or other laboratory abnormalities noted. The kinetic evaluation resulted in a biological half-life for MBOCA in urine of approximately 23 hours. Assuming a one-compartment model, approximately 94% of an initial MBOCA dose will be eliminated within four days. This is the first report of kinetic analysis on urinary MBOCA excretion in humans. This information suggests that biological monitoring of the urine MBOCA concentrations in exposed workers may miss peak levels following an acute exposure unless the analyses of the urinary MBOCA are performed in a timely fashion. Recommendations to the company included: 1) installation of a warning system or lock-out device on the mixing machine to prevent the opening of the MBOCA hose prior to the release of pressure; and 2) annual medical surveillance of this individual for bladder cancer with urinalysis and urine cytology.

Accidents, Occupational↗
PubMed1986

A cytogenetic study of papaya workers exposed to ethylene dibromide.

Ethylene dibromide (EDB) has been shown to be carcinogenic in animal studies and mutagenic in vitro. One cytogenetic study of workers exposed to low levels of EDB for short durations was negative. To test whether exposure to low levels of EDB over long periods caused cytogenetic changes, we have assessed the frequencies of sister-chromatid exchanges (SCE) and chromosomal aberrations (CA) in the peripheral blood lymphocytes of 60 men occupationally exposed to EDB. These men worked in papaya-packing plants where EDB was used to fumigate the fruit after harvest to kill fruit-fly larvae. 42 other men who worked at a nearby sugar mill served as controls. The average duration of exposure of the papaya workers was 5 years. 82 full shift personal breathing-zone air samples indicated that the papaya workers were exposed to a geometric mean of 88 ppb of EDB, as an 8-h time weighted average (TWA). Peaks up to 262 ppb were measured. The proposed OSHA 8-h TWA for EDB is 100 ppb, while NIOSH recommends 45 ppb. No differences in SCE levels were found between exposed and nonexposed workers. No differences were found in the total CA frequency between exposed and nonexposed workers. SCE levels were significantly increased in men who smoked cigarettes (p = 0.0001) and in men who smoked marijuana (p = 0.01). CA levels showed a significant increasing trend with age (p = 0.03).

Adult↗
PubMed1986

Efficacy of urinary monitoring for 4,4'-methylenebis (2-chloroaniline).

The aromatic amine 4,4'-methylenebis (2-chloroaniline) (MBOCA), an animal carcinogen, is used commercially as a curing agent for isocyanate-containing polymers. It is structurally similar to other aromatic amines that cause bladder cancer in occupationally exposed workers. Since the late 1970s, MBOCA users have relied on urinary monitoring as the primary method of assessing MBOCA exposure in the workplace. This paper (1) outlines uncertainties about MBOCa's metabolism in humans that complicate interpretation of urinary MBOCA results; (2) describes alternative laboratory techniques for measuring MBOCA in urine; and (3) discusses observations from site visits concerning the practical application of urinary monitoring. Recommendations to improve the efficacy of monitoring programs for urinary MBOCA are outlined.

Animals↗
PubMed1985

Cytogenetic studies in humans after short-term exposure to ethylene dibromide.

Ethylene dibromide (EDB) has been shown to increase sister chromatid exchange in animal cells in vitro, but its cytogenetic effects in humans have not been previously studied. A solution containing EDB is used in the summer months in Colorado to spray felled pine trees to kill pine beetles. We have assessed the frequencies of sister chromatid exchanges and chromosomal aberrations in the peripheral blood lymphocytes of 14 sprayers both before and after exposure. Six nonexposed individuals also were tested. Full-shift personal breathing-zone air samples indicated that the sprayers were exposed to an average of 60 ppb of EDB, as an eight-hour time weighted average. The range of exposure was from 5 to 281 ppb. Workers sprayed EDB for only five to 26 days during the summer, with an average of 14 days. After adjusting for smoking and the use of prescription medicine, there was no statistically significant difference between the frequencies of either sister chromatid exchange or chromosomal aberrations before and after spraying.

Adult↗
PubMedDate not supplied

Emotional responses to infertility. Nursing interventions.

Couples and individuals vary in their responses to the infertility experience. The specific emotional stages that couples and individuals pass through as they cope with their infertility are discussed. Appropriate nursing interventions are suggested for each specific stage.

Anger↗