A closed formula for calculating pesticide residue levels in the feed items of terrestrial species.

Calculating pesticide residue levels in feed items for terrestrial species requires accounting for the application rate of the pesticide, the frequency and interval of application, the half-life of the pesticide on the food item, and the residue unit dose. Microsoft Excel™-based applications such as the US Environmental Protection Agency's Terrestrial Residue Exposure model (T-REX) and Terrestrial Herpetofaunal Exposure Residue Program (T-HERPS) calculate the residue levels in feed items using a recursive sequence. A recursive sequence is an unwieldy calculation method that presents a barrier to creating a software-based tool capable of conducting flexible assessments. Therefore, we determined the closed form of the recursive mathematical equation used by both T-REX and T-HERPS. With this formula, we can both duplicate screening-level assessments (T-REX, T-HERPS) as well as incrementally refine the assessment with data-driven inputs. Integr Environ Assess Manag 2018;14:703-709. © 2018 SETAC.

Synergistic effect of piperonyl butoxide on acute toxicity of pyrethrins to Hyalella azteca.

A series of acute toxicity tests with the amphipod Hyalella azteca was performed to quantify the synergistic effect of piperonyl butoxide (PBO) on pyrethrin toxicity. Concentrations of PBO <4 µg/L caused no toxicity enhancement, whereas toxicity increased with PBO concentrations between 4 µg/L and 15 µg/L. Additive toxicity calculations showed that true synergism accounted for an increase in pyrethrin toxicity (decrease in median lethal concentration) of 1.4-fold to 1.6-fold and varied only slightly between 4 µg/L and 15 µg/L PBO, whereas direct toxicity of PBO accounted for an additional increase in mixture toxicity (up to 3.2-fold) that was proportional to PBO concentration. The results can be used to assess the risk of measured or predicted co-occurring concentrations of PBO and pyrethrins in surface waters. Environ Toxicol Chem 2016;35:2111-2116. © 2016 SETAC.

Efficacy and safety of ephedra and ephedrine for weight loss and athletic performance: a meta-analysis.

CONTEXT: Ephedra and ephedrine sometimes are used for weight loss or enhanced athletic performance, but the efficacy and safety of these compounds are uncertain. OBJECTIVE: To assess the efficacy and safety of ephedra and ephedrine used for weight loss and enhanced athletic performance. DATA SOURCES: We searched 9 databases using the terms ephedra, ephedrine, adverse effect, side effect, efficacy, effective, and toxic. We included unpublished trials and non-English-language documents. Adverse events reported to the US Food and Drug Administration MedWatch program were assessed. STUDY SELECTION: Eligible studies were controlled trials of ephedra or ephedrine used for weight loss or athletic performance and case reports of adverse events associated with such use. Eligible studies for weight loss were human studies with at least 8 weeks of follow-up; and for athletic performance, those having no minimum follow-up. Eligible case reports documented that ephedra or ephedrine was consumed within 24 hours prior to an adverse event or that ephedrine or an associated product was found in blood or urine, and that other potential causes had been excluded. Of the 530 articles screened, 52 controlled trials and 65 case reports were included in the adverse events analysis. Of more than 18 000 other case reports screened, 284 underwent detailed review. DATA EXTRACTION: Two reviewers independently identified trials of efficacy and safety of ephedra and ephedrine on weight loss or athletic performance; disagreements were resolved by consensus. Case reports were reviewed with explicit and implicit methods. DATA SYNTHESIS: No weight loss trials assessed duration of treatment greater than 6 months. Pooled results for trials comparing placebo with ephedrine (n = 5), ephedrine and caffeine (n = 12), ephedra (n = 1), and ephedra and herbs containing caffeine (n = 4) yielded estimates of weight loss (more than placebo) of 0.6 (95% confidence interval, 0.2-1.0), 1.0 (0.7-1.3), 0.8 (0.4-1.2), and 1.0 (0.6-1.3) kg/mo, respectively. Sensitivity analyses did not substantially alter the latter 3 results. No trials of ephedra and athletic performance were found; 7 trials of ephedrine were too heterogeneous to synthesize. Safety data from 50 trials yielded estimates of 2.2- to 3.6-fold increases in odds of psychiatric, autonomic, or gastrointestinal symptoms, and heart palpitations. Data are insufficient to draw conclusions about adverse events occurring at a rate less than 1.0 per thousand. The majority of case reports are insufficiently documented to allow meaningful assessment. CONCLUSIONS: Ephedrine and ephedra promote modest short-term weight loss (approximately 0.9 kg/mo more than placebo) in clinical trials. There are no data regarding long-term weight loss, and evidence to support use of ephedra for athletic performance is insufficient. Use of ephedra or ephedrine and caffeine is associated with increased risk of psychiatric, autonomic, or gastrointestinal symptoms, and heart palpitations.