Age-related hepatitis B seroconversion rates in health care workers.

BACKGROUND: Protective hepatitis titers are reported for more than 90% of healthy adults who received three intradeltoid injections of vaccine. Some factors that influence seroconversion rates include age, sex, and presence of chronic diseases. METHODS: Because of work-related factors that placed them at risk of acquiring hepatitis B, 112 employees, who ranged in age from 20 to 70 years with a mean age of 39.2 years, completed the hepatitis B vaccination series between 1986 and 1993. All participants received three vaccinations. RESULTS: Hepatitis B surface antibody did not develop in 16 of 112 recipients (14.2%, 95% CI, 7.6% to 20.8%). Race, sex, and duration to antibody titer did not affect rates of seroconversion. Age greater than 50 years was associated with significantly decreased seroconversion rates (64.7%, 95% CI, 42.0% to 87.4%) compared with seroconversion rates of those younger than 50 years of age (89.5%, 95% CI 83.3% to 95.7%, p = 0.02). CONCLUSIONS: Our results indicate that when a hepatitis B immunization program is implemented, seroconversion rates are lower than published rates for healthy adults and adolescents. We recommend that seroconversion data from immunization programs for employees at risk for hepatitis B be reviewed and that postimmunization testing be considered to ensure adequate protection for those employees at highest risk for nonconversion.

Prevalence of congenital deficiency in serum cholinesterase.

The most economical blood test for the monitoring of workers who are exposed to organophosphate pesticides is serum cholinesterase; however, serum cholinesterase can be affected by conditions other than pesticide exposure. The results of studies in Europe indicate a 4% prevalence of congenital serum cholinesterase deficiency. Prevalence rates in the United States have not been reported. In this study, 127 workers who were part of an employee health program were evaluated. Workers who had decreased serum cholinesterase levels on baseline testing before pesticide exposure were evaluated for a congenital deficit in serum cholinesterase. Five (3.9%) individuals had baseline measurements below the laboratory normal reference value: 4 (3.1 %) were heterozygote for the deficiency, and the remaining individual did not return to test for the genetic deficiency. No one was found to have the homozygote deficiency. The prevalence of congenital deficiency in serum cholinesterase in a midwestern population was 3.1-3.9%. We found it useful to incorporate the knowledge of who has a congenital deficiency into our employee health program, the purpose of which is to monitor workers who spray organophosphates.

Identification of female-produced sex pheromone from banded cucumber beetle,Diabrotica balteata leconte (Coleoptera: Chrysomelidae).

A sex pheromone produced by female banded cucumber beetle adults,Diabrotica balteata LeConte, was isolated from volatiles trapped on Porapak Q and identified as 6,12-dimethylpentadecan-2-one. The structure was elucidated by spectroscopic analyses and confirmed by synthesis. The synthesized racemic compound was equal to the purified natural pheromone in eliciting responses by banded cucumber beetle males to field traps. A doseresponse characteristic was demonstrated for the racemic material formulated on filter paper or rubber septa and placed in field traps. The absolute configuration at the C-6 and C-12 positions was not established.

Response of northern corn rootworm,Diabrotica barberi Smith and Lawrence, to stereoisomers of 8-methyl-2-decyl propanoate.

The four stereoisomers of 8-methyl-2-decyl propanoate were tested in South Dakota for attractiveness to the northern corn rootworm,Diabrotica barberi Smith and Lawrence (NCR). Only the 2R,8R configuration was attractive to the NCR. Inhibition of the NCR response to 2R,8R occurred when either the 2S,8R or 2S,8S isomers were components of the pheromone source. The 2R,8S configuration elicited no behavioral activity in the NCR.

Response ofDiabrotica virgifera virgifera, D. v. Zeae, andD. porracea to stereoisomers of 8-methyl-2-decyl propanoate.

The four stereoisomers of 8-methyl-2-decyl propanoate were tested in the United States and Mexico for attractiveness toDiabrotica virgifera virgifera LeConte, the western corn rootworm,D. v. zeae Krysan and Smith, the Mexican corn rootworm, andD. porracea Harold. Males ofD. v. virgifera andD. v. zeae responded strongly to the (2R,8R)-isomer and secondarily to (2S,8R), whileD. ponacea responded exclusively to the (2S,8R)-isomer. The (2S,8S)- and (2R,8S)-isomers were inactive in all tests. Synergism or inhibition was not detected when various mixtures of the isomers were tested withD. v. virgifera. These phenomena were not tested withD. v. zeae andD. ponacea.

Identification of a female-produced sex pheromone from the southern corn rootworm,Diabrotica undecimpunctata howardi Barber.

A sex pheromone has been isolated and identified from virgin females of the southern corn rootworm (SCR),Diabrotica undecimpunctata howardi Barber. The synthesized compound, 10-methyl-2-tridecanone was shown to be attractive to males of the SCR, and also to males ofD. u. undecimpunctata Mannerheim, the western spotted cucumber beetle (WSCB), and ofD. u. duodecimnotata in Mexico. Males of both the SCR and the WSCB strongly preferred theR over theS enantiomer. The resolved enantiomers were not tested againstD. u. duodecimnotata.

Identification of a female-produced sex pheromone of the western corn rootworm.

A sex pheromone has been isolated and identified from virgin females of the western corn rootworm (WCR),Diabrotica virgifera virgifera LeConte. The synthesized compound, racemic 8-methyl-2-decanol propanoate, was equal in attraction to the natural pheromone when tested in the field as a trap bait against three taxa ofDiabrotica known to respond to pheromone extracts from female WCR. Five taxa (D. virgifera virgifera; D. virgifera zeae Krysan and Smith, Mexican corn rootworm;D. longicornis barberi Smith and Lawrence, northern corn rootworm;D. longicornis longicornis (Say); andD. porracea Harold) were attracted to traps baited with 8-methyl-2-decanol propanoate. The response of male northern corn rootworms (NCR) in the field peaked at a relatively low concentration of 8-methyl-2-decanol propanoate and then was severely reduced at the higher concentrations tested. Conversely, the response of male WCR in the field continued to increase up to the highest dose tested.