Editor's Highlight: Genetic Targets of Acute Toluene Inhalation in Drosophila melanogaster

Interpretation and use of data from high-throughput assays for chemical toxicity require links between effects at molecular targets and adverse outcomes in whole animals. The well-characterized genome of Drosophila melanogaster provides a potential model system by which phenotypic responses to chemicals can be mapped to genes associated with those responses, which may in turn suggest adverse outcome pathways associated with those genes. To determine the utility of this approach, we used the Drosophila Genetics Reference Panel (DGRP), a collection of ∼200 homozygous lines of fruit flies whose genomes have been sequenced. We quantified toluene-induced suppression of motor activity in 123 lines of these flies during exposure to toluene, a volatile organic compound known to induce narcosis in mammals via its effects on neuronal ion channels. We then applied genome-wide association analyses on this effect of toluene using the DGRP web portal (http://dgrp2.gnets.ncsu.edu), which identified polymorphisms in candidate genes associated with the variation in response to toluene exposure. We tested ∼2 million variants and found 82 polymorphisms located in or near 66 candidate genes that were associated with phenotypic variation for sensitivity to toluene at P < 5 × 10-5, and human orthologs for 52 of these candidate Drosophila genes. None of these orthologs are known to be involved in canonical pathways for mammalian neuronal ion channels, including GABA, glutamate, dopamine, glycine, serotonin, and voltage sensitive calcium channels. Thus this analysis did not reveal a genetic signature consistent with processes previously shown to be involved in toluene-induced narcosis in mammals. The list of the human orthologs included Gene Ontology terms associated with signaling, nervous system development and embryonic morphogenesis; these orthologs may provide insight into potential new pathways that could mediate the narcotic effects of toluene.

Effects of toluene, acrolein and vinyl chloride on motor activity of Drosophila melanogaster

The data generated by current high-throughput assays for chemical toxicity require information to link effects at molecular targets to adverse outcomes in whole animals. In addition, more efficient methods for testing volatile chemicals are needed. Here we begin to address these issues by determining the utility of measuring behavioral responses of Drosophila melanogaster to airborne volatile organic compounds (VOCs) as a potential model system for discovering adverse outcome pathways and as a method to test for toxicity. In these experiments, we measured motor activity in male and female flies to determine concentration-effect functions for three VOCs that differ in their mode of action: toluene, a narcotic; acrolein, an irritant; and vinyl chloride, a hepatocarcinogen. These experiments were conducted in Flyland, an outbred population of flies derived from 40 lines of the Drosophila Genetics Reference Panel (DGRP) (Mackay et al., 2012), in preparation for subsequent experiments with individual lines of the DGRP. Systematic, concentration-related changes in activity were observed with toluene, but not with acrolein; high concentrations of vinyl chloride reduced activity by a small amount. Despite higher activity levels in males than in females under control conditions, the sexes were equally sensitive to toluene. Transient increases in activity at the onset and offset of exposure to toluene and vinyl chloride suggested that the flies detected changes in air quality at concentrations that did not persistently suppress activity. The effects and potency of toluene are consistent with those observed in rodents. The lack of clear concentration-related changes in response to acrolein and vinyl chloride shows limitations of this method is for screening toxicity attributed to VOCs. This abstract does not reflect U.S. EPA policy.

Prevalence and risk factors of chorioamnionitis among adolescents

OBJECTIVE

To identify the prevalence of chorioaminionitis and unique risk factors for this disorder among adolescents under 18 years of age.

METHODS

At their first prenatal visit we interviewed 352 adolescents who received prenatal care and delivered an infant at our institution between April 20, 1992, and November 10, 1994, to elicit information on demographic characteristics and behavioral risk factors. Retrospective chart review confirmed the presence of chorioamnionitis using accepted clinical criteria. We determined reproductive history, evidence of sexually transmitted disease, duration of labor, use of oxytocin, an internal uterine pressure monitor or conduction anesthesia, timing and duration of ruptured membranes, type of delivery, and infant birth weight from review of subjects' charts. Logistic regression analysis was used to develop adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for risk factors of chorioaminionitis.

RESULTS

Ten percent (34 of 352) of adolescents met the clinical definition for chorioamnionitis. Alcohol and tobacco use during pregnancy (OR 7.6; 95% CI 2.3, 25.8) and being married or living with a partner (OR 2.7; 95% CI 1.1, 6.5) were significantly associated with chorioamnionitis, as was conduction anesthesia (OR 4.1; 95% CI 1.1, 15.4), a second stage labor longer than 2 hours (OR 3.5; 95% CI 1.4, 8.5), and rupture of the membranes longer than 18 hours (OR 6.9; 95% CI 2.5, 18.9). Parity or preterm delivery did not differ significantly between those with or without chorioamnionitis.

CONCLUSION

These data suggest that in addition to risk factors observed in adults, adolescents who concurrently use tobacco and alcohol during pregnancy, are married or living with a male partner, and have conduction anesthesia are at increased risk for chorioamnionitis.

Human immunodeficiency virus: healthcare worker safety issues

No country or social group is immune from acquiring the human immunodeficiency virus. Among healthcare workers, nurses account for a large percentage of people who seroconvert accidentally. This article will provide a review of the status of the acquired immune deficiency syndrome epidemic, discuss infection control guidelines, and suggest prophylactic measures for the prevention of transmission in the healthcare setting.

Cues to action in prostate cancer screening

PURPOSES/OBJECTIVES

To describe factors that cue men of all ages to participate in prostate cancer screening programs and to explore the relationship of age to the rating of the cues.

DESIGN

Exploratory survey.

SETTING

A large community prostate cancer screening program in the Midwest.

SAMPLE

127 men (mean = 66.3 years of age) who participated in community prostate screening.

METHODS

Subjects completed and returned by mail the 13-item Prostate Screening Follow-Up Questionnaire developed, piloted, and refined by the investigator for measuring the rating of the cues to action.

MAIN OUTCOME MEASURES

Results of the rating of each cue to action, selected demographic variables, and comparison of the cue ratings by age group.

FINDINGS

Appointment scheduling, reminder cards, a friend/family member with cancer, and newspaper promotion were perceived by the sample as most influential in their decision to have prostate cancer screening. No practical significant differences in cue ratings were found between the two age groups: 70 years of age and older and less than 70 years of age.

CONCLUSION

Reminder cards, specific appointments, and newspaper promotion should be used when structuring community prostate cancer screening programs. Men who have a friend or family member with cancer may be more likely to participate in screening activities.

IMPLICATIONS FOR NURSING PRACTICE

By incorporating influential cues to action into their everyday practice, nurses can be instrumental in reaching the population of men who are at risk for prostate cancer. Strategies for promoting prostate cancer screening should include: educating patients and family members about prostate cancer screening guidelines, using specific influential promotional practices when setting up prostate screening programs, and networking with seniors programs in the community.

Complications of intravenous therapy: a randomized prospective study--Vialon vs. Teflon

For the past two decades, the vast majority of vascular-access devices used in I.V. catheterization have been made of Teflon material. More recent developments in material science have produced the Vialon biomaterial currently used in the Insyte I.V. catheter. This prospective, randomized study compared the length of venous dwell time and rate of I.V.-related complications of Teflon peripheral I.V. catheters and Vialon peripheral I.V. catheters. The study population included only the most difficult peripheral I.V. access patients. Conditions of insertion, monitoring, and care were carefully controlled by the investigators. An alternate assignment scheme was used for randomization of eligible patients. Of 247 catheters evaluated over a six-week period in a 550-bed community tertiary care hospital, 191 were evaluable; of these, equivalent numbers were made of Vialon and Teflon. This investigation found that the incidence of phlebitis in the group receiving Vialon I.V. catheters was 36 percent lower than that of the group receiving Teflon I.V. catheters.

Responses of photosynthetic O2 evolution to PPFD in the CAM epiphyte Tillandsia usneoides L. (Bromeliaceae)

Past studies of the effects of varying levels of photosynthetic photon flux density (PPFD) on the morphology and physiology of the epiphytic Crassulacean acid metabolism (CAM) plant Tillandsia usneoides L. (Bromeliaceae) have resulted in two important findings: (1) CAM, measured as integrated nocturnal CO2 uptake or as nocturnal increases in tissue acidity, saturates at relatively low PPFD, and (2) this plant does not acclimate to different PPFD levels, these findings require substantiation using photosynthetic responses immediately attributable to different PPFD levels, e.g., O2 evolution, as opposed to the delayed, nocturnal responses (CO2 uptake and acid accumulation). In the present study, instantaneous responses of O2 evolution to PPFD level were measured using plants grown eight weeks at three PPFD (20-45, 200-350, and 750-800 μmol m(-2)s(-1)) in a growth chamber, and using shoots taken from the exposed upper portions (maximum PPFD of 800 μmol m(-2)s(-1)) and shaded lower portions (maximum PPFD of 140 μmol m(-2)s(-1)) of plants grown ten years in a greenhouse. In addition, nocturnal increases in acidity were measured in the growth chamber plants. Regardless of the PPFD levels during growth, O2 evolution rates saturated around 500 μmol m(-2)s(-1). Furthermore, nocturnal increases in tissue acidity saturated at much lower PPFD. Thus, previous results were confirmed: photosynthesis saturated at low PPFD, and this epiphyte does not acclimate to different levels of PPFD.

The cellblock token economy: token reinforcement procedures in a maximum security correctional institution for adult male felons

Two experiments were conducted (1) to explore the application of token reinforcement procedures in a maximum security correctional institution for adult male felons and (2) to determine to what extent the reinforcement procedures disrupted the day-to-day lives of inmate participants. In Experiment 1, an expanded reversal design revealed that the combination of praise and token reinforcement was more effective than the combinations of praise and noncontingent token award or direct commands on four common institutional activities. The latter two combinations were not found to be any more effective than praise alone. Experiment 2, which also employed a reversal design, indicated that the high levels of performance observed during the token reinforcement phases of Experiment 1 could be attained without subjecting participants to undue hardship in the form of increased deprivation of either social intercourse or the opportunity to engage in recreational and entertainment activities. Client safeguards are discussed in detail.

Programmed instruction for institutionalized offenders: contingency management and performance contracts

Contractual agreements and contingency management procedures were used in an attempt to increase the productivity of 16 prison inmates studying programmed educational materials. Programmed instruction requires that S respond in a verbal (written) manner to specially constructed questions and/or statements. A question or statement and its corresponding response constitute a “frame.” Ss agreed to complete a progressively greater number of frames per week during an E-management phase. Work was assigned daily by means of a performance contract. During a subsequent self-management phase Ss contracted with themselves to produce more frames than they had completed during the baseline. Following completion of a unit of work during the E-management and self-management phases, S was allowed a 15-min. period in which he could either select an item from a reinforcement menu or opt to return to the study area. Under contingency-management procedures Ss successfully completed the work assigned at first by E and later by themselves. Increased amounts of work were accompanied by greater work efficiency; total time in the work area per day decreased, and the number of frames completed per hour increased. Test performance was better during the contingency-management phases than in the baseline phase.