Matthew Kramer

Plant sterol esters lower plasma lipids and most carotenoids in mildly hypercholesterolemic adults.

The ability of plant sterol esters (PSE) in salad dressing to modify plasma lipids and carotenoids was determined in 26 men and 27 women fed controlled, weight-maintaining, isocaloric diets. Diets contained typical American foods that provided 32% of energy from fat. Dressings contained 8 g (ranch) or 4 g (Italian) of fat per serving. PSF (3.6 g/d) were provided in two servings/d of one of the dressings. Diets with ranch or Italian dressing without and with PSE were fed for 3 wk/diet and crossed over randomly within dressings. Diets were adjusted to similar fat and fatty acid concentrations. Type of salad dressing did not affect plasma lipids, lipoproteins, carotenoids, or fat-soluble vitamins (P>0.05). Switching from a self-selected baseline diet to the control diet resulted in reduction in low density lipoprotein (LDL) cholesterol of 7.9%, a decrease in high density lipoprotein (HDL) cholesterol of 3.1%, and a decrease in triglycerides (TG) of 9.3%. Consumption of 3.6 g of PSE resulted in further decreases in LDL cholesterol (9.7%) and TG (7.3%) but no additional change in HDL cholesterol. Total plasma carotenoids decreased 9.6% with PSE. An automated stepwise procedure was developed to produce candidate mixed models relating plasma carotenoid response to PSE. These models adjusted for preintervention plasma carotenoid levels and effects of diets on blood lipids. There were significant decreases in β-carotene, α-carotene, and β-cryptoxanthin (females only) not associated with changes in plasma lipids. Plasma carotenoids on all diets remained within normal ranges. We conclude that low-fat foods, such as salad dressings, are effective carriers for PSE.

Statistical guidelines for Apis mellifera research

Summary In this article we provide guidelines on statistical design and analysis of data for all kinds of honey bee research. Guidelines and selection of different methods presented are, at least partly, based on experience. This article can be used: to identify the most suitable analysis for the type of data collected; to optimise ones experimental design based on the experimental factors to be investigated, samples to be analysed, and the type of data produced; to determine how, where, and when to sample bees from colonies; or just to inspire. Also included are guidelines on presentation and reporting of data, as well as where to find help and which types of software could be useful.

A new in vitro bioassay system for discovery of novel human-use mosquito repellents

ABSTRACT A Klun & Debboun (K&D) test module, previously developed and used for quantitative measurement of the efficacy of mosquito repellents on human volunteers, was adapted for in vitro evaluation of repellents by coupling the module with a membrane-blood reservoir. Performance of Deet, Bayrepel®, and SS-220 insect repellents in the new in vitro system was compared with their performance on humans against mosquitoes using our standard in vivo system. For each compound, in vitro dose–response assays were conducted with compounds applied to cloth positioned over blood reservoirs covered with Baudruche membrane against Aedes aegypti. The repellents were also tested in vitro against Anopheles stephensi and Ae. aegypti at a fixed dose of 24 nmol compound/cm2 cloth over the Baudruche and Edicol collagen membranes. Concurrently, the repellents were tested at the fixed dose using the K&D module on human volunteers. The observed proportions of both mosquito species deterred from biting in the fixed doses in the in vitro assays were similar to those obtained using humans, being clearly able to distinguish controls from repellents, and differing only in the ranking of the effectiveness of some of the repellents. Dose–response relationships of the in vitro and in vivo systems were also very similar, although not directly comparable because the data were not collected concurrently. This new in vitro assay system can be used in high throughput screening of compounds to identify new repellents having potential for use as topical mosquito repellents on humans.

Identifying sources of reporting error using measured food intake.

Objective:To investigate the magnitude and relative contribution of different sources of measurement errors present in the estimation of food intake via the 24-h recall technique.Design:We applied variance decomposition methods to the difference between data obtained from the USDAs Automated Multiple Pass Method (AMPM) 24-h recall technique and measured food intake (MFI) from a 16-week cafeteria-style feeding study. The average and the variance of biases, defined as the difference between AMPM and MFI, were analyzed by macronutrient content, subject and nine categories of foods.Subjects:Twelve healthy, lean men (age, 39±9 year; weight, 79.9±8.3 kg; and BMI, 24.1±1.4 kg/m2).Results:Mean food intakes for AMPM and MFI were not significantly different (no overall bias), but within-subject differences for energy (EI), protein, fat and carbohydrate intakes were 14, 18, 23 and 15% of daily intake, respectively. Mass (incorrect portion size) and deletion (subject did not report foods eaten) errors were each responsible for about one-third of the total error. Vegetables constituted 8% of EI but represented >25% of the error across macronutrients, whereas grains that contributed 32% of EI contributed only 12% of the error across macronutrients.Conclusions:Although the major sources of reporting error were mass and deletion errors, individual subjects differed widely in the magnitude and types of errors they made.

Israeli acute paralysis virus: epidemiology, pathogenesis and implications for honey bee health

Israeli acute paralysis virus (IAPV) is a widespread RNA virus of honey bees that has been linked with colony losses. Here we describe the transmission, prevalence, and genetic traits of this virus, along with host transcriptional responses to infections. Further, we present RNAi-based strategies for limiting an important mechanism used by IAPV to subvert host defenses. Our study shows that IAPV is established as a persistent infection in honey bee populations, likely enabled by both horizontal and vertical transmission pathways. The phenotypic differences in pathology among different strains of IAPV found globally may be due to high levels of standing genetic variation. Microarray profiles of host responses to IAPV infection revealed that mitochondrial function is the most significantly affected biological process, suggesting that viral infection causes significant disturbance in energy-related host processes. The expression of genes involved in immune pathways in adult bees indicates that IAPV infection triggers active immune responses. The evidence that silencing an IAPV-encoded putative suppressor of RNAi reduces IAPV replication suggests a functional assignment for a particular genomic region of IAPV and closely related viruses from the Family Dicistroviridae, and indicates a novel therapeutic strategy for limiting multiple honey bee viruses simultaneously and reducing colony losses due to viral diseases. We believe that the knowledge and insights gained from this study will provide a new platform for continuing studies of the IAPV–host interactions and have positive implications for disease management that will lead to mitigation of escalating honey bee colony losses worldwide.

Synthesis and Repellent Efficacy of a New Chiral Piperidine Analog: Comparison with Deet and Bayrepel Activity in Human-Volunteer Laboratory Assays Against Aedes aegypti and Anopheles stephensi

Abstract Optically active (1S, 2′S)-2-methylpiperidinyl-3-cyclohexen-1-carboxamide (SS220) is a new synthetic arthropod repellent. A three-step synthesis based on a chiral Diels-Alder reaction and diastereomeric resolution of 2-methylpiperidine was developed to prepare the compound. Quantitative laboratory assays using human volunteers compared the effectiveness of SS220 with the commonly used repellents Deet and Bayrepel against Aedes aegypti (Linnaeus) and Anopheles stephensi Liston mosquitoes. In two experiments using Aedes aegypti, one using a single identical dose and one with varying doses used to develop a dose–response curve, SS220 was as effective as Deet and both compounds were more effective than Bayrepel. The three compounds were equally effective against An. stephensi. Based on the ease of its synthetic preparation and its repellent efficacy, we surmise that SS220 is a candidate to serve as a new and effective alternate repellent for protection against arthropod disease vectors.

Comparison of two different physical activity monitors

BackgroundUnderstanding the relationships between physical activity (PA) and disease has become a major area of research interest. Activity monitors, devices that quantify free-living PA for prolonged periods of time (days or weeks), are increasingly being used to estimate PA. A range of different activity monitors brands are available for investigators to use, but little is known about how they respond to different levels of PA in the field, nor if data conversion between brands is possible.Methods56 women and men were fitted with two different activity monitors, the Actigraph™ (Actigraph LLC; AGR) and the Actical™ (Mini-Mitter Co.; MM) for 15 days. Both activity monitors were fixed to an elasticized belt worn over the hip, with the anterior and posterior position of the activity monitors randomized. Differences between activity monitors and the validity of brand inter-conversion were measured by t-tests, Pearson correlations, Bland-Altman plots, and coefficients of variation (CV).ResultsThe AGR detected a significantly greater amount of daily PA (216.2 ± 106.2 vs. 188.0 ± 101.1 counts/min, P < 0.0001). The average difference between activity monitors expressed as a CV were 3.1 and 15.5% for log-transformed and raw data, respectively. When a conversion equation was applied to convert datasets from one brand to another, the differences were no longer significant, with CVs of 2.2 and 11.7%, log-transformed and raw data, respectively.ConclusionAlthough activity monitors predict PA on the same scale (counts/min), the results between these two brands are not directly comparable. However, the data are comparable if a conversion equation is applied, with better results for log-transformed data.

Comparative Activity of Deet and AI3-37220 Repellents Against the Ticks Ixodes scapularis and Amblyomma americanum (Acari: Ixodidae) in Laboratory Bioassays

Abstract The repellents N,N-diethyl-3-methylbenzamide (deet) and racemic 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (AI3-37220) were evaluated using two different laboratory bioassays to determine their relative effectiveness against host-seeking nymphs of the blacklegged tick, Ixodes scapularis Say, and the lone star tick, Amblyomma americanum (L.). In a petri dish bioassay, ticks were released within a ring of repellent on a horizontal filter paper disk. In the second bioassay, ticks were allowed to climb a vertical strip of filter paper whose central portion was treated with a repellent. Deet and AI3-37220 were more effective against I. scapularis than A. americanum nymphs. In the petri dish bioassay, none of the concentrations of deet or AI3-37220 tested confined A. americanum within the treated ring. However, in the vertical bioassay, both species exhibited avoidance of the repellents, and I. scapularis was repelled by much lower concentrations than A. americanum. I. scapularis were repelled by lower concentrations in the vertical bioassay than in the petri dish bioassay. Deet was slightly more effective against I. scapularis than AI3-37220 in both bioassays, but AI3-37220 was significantly more effective than deet against A. americanum in the vertical bioassay.

Comparative Resistance of Anopheles albimanus and Aedes aegypti to N,N-Diethyl-3-methylbenzamide (Deet) and 2-Methylpiperidinyl-3-cyclohexen-1-carboxamide (AI3-37220) in Laboratory Human-Volunteer Repellent Assays

Abstract The insect repellents N,N-diethyl-3-methylbenzamide (Deet) and the racemate and 1S,2′S stereoisomer of 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (AI3-37220) were tested against Anopheles albimanus Wiedemann and Aedes aegypti (L.) in laboratory human-volunteer assays. Estimated skin doses of Deet or racemic AI3–37220 required to reduce biting by 95% in Ae. aegypti were 2.3 and 3.5 × 10–2 μmol/cm2 skin, respectively, whereas estimated doses for 95% bite reduction of An. albimanus in an ≈40-yr-old laboratory colony established from El Salvador were 5 times higher at 12 × 10–2 μmol Deet/cm2 skin and >20 × 10–2 μmol/cm2 skin for AI3-37220. In tests with the 1S,2′S stereoisomer of AI3-37220, a newly established colony of An. albimanus from Belize bit less aggressively than El Salvador An. albimanus. However, the Belize-derived mosquitoes were as resistant as the old El Salvador colony to repellent effects of 1S,2′S stereoisomer of 2-methylpiperidinyl-3-cyclohexene-1-carboxamide. Earlier workers surmised that usual skin doses of Deet would offer only limited protection against An. albimanus in the field. Our findings support this speculation, but they also indicate that doses of Deet higher than those needed for protection against Ae. aegypti might offer reasonable protection against An. albimanus. Results indicate that neither racemate nor 1S,2′S stereoisomer of 2-methylpiperidinyl-3-cyclohexene-1-carboxamide offer as much protection as Deet against An. Albimanus, despite being highly effective against Ae. aegypti.

Feeding Deterrent Effects of Catnip Oil Components Compared with Two Synthetic Amides Against Aedes aegypti

Abstract Recently, catnip, Nepeta cataria L. (Lamiaceae), essential oil has been formulated and marketed as an alternative repellent for protection against biting arthropods by several vendors. We isolated the major active components of catnip oil, E,Z- and Z,E-nepetalactone, and quantitatively measured their antibiting efficacy compared with the repellents N,N-diethyl-3-methylbenzamide (deet) and chiral (1S,2′S)-2-methylpiperidinyl-3-cyclohexene-1-carboxamide (SS220) against the yellowfever mosquito, Aedes aegypti (L.), by using an in vitro assay and human volunteers at 24 nmol compound/cm2 (cloth or skin). Of all compounds tested in an in vitro assay, SS220 ranked as the most effective, whereas catnip oil and the nepetalactone compounds did not differ significantly from each other or from deet. However, in human volunteer bioassays, neither E,Z and Z,E-nepetalactone nor racemic nepetalactone deterred mosquito biting as effectively as SS220 or deet. All compounds differed significantly from the control. We conclude that catnip oil and nepetalactone isomers are significantly less effective than deet or SS220 in deterring the biting of Ae. aegypti.