CD209a Synergizes with Dectin-2 and Mincle to Drive Severe Th17 Cell-Mediated Schistosome Egg-Induced Immunopathology

The immunopathology caused by schistosome helminths varies greatly in humans and among mouse strains. A severe form of parasite egg-induced hepatic granulomatous inflammation, seen in CBA mice, is driven by Th17 cells stimulated by IL-1β and IL-23 produced by dendritic cells that express CD209a (SIGNR5), a C-type lectin receptor (CLR) related to human DC-SIGN. Here, we show that CD209a-deficient CBA mice display decreased Th17 responses and are protected from severe immunopathology. In vitro, CD209a augments the egg-induced IL-1β and IL-23 production initiated by the related CLRs Dectin-2 and Mincle. While Dectin-2 and Mincle trigger an FcRγ-dependent signaling cascade that involves the tyrosine kinase Syk and the trimolecular Card9-Bcl10-Malt1 complex, CD209a promotes the sustained activation of Raf-1. Our findings demonstrate that CD209a drives severe Th17 cell-mediated immunopathology in a helminthic disease based on synergy between DC-SIGN- and Dectin-2-related CLRs.

Prospective, comparative effectiveness trial of cow's milk elimination and swallowed fluticasone for pediatric eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic, immune-mediated disease in which food antigens play a key role. Current therapeutic options are limited to long-term steroid medication and dietary elimination of multiple foods, each of which is challenging. Our objective was to compare single food elimination of cow's milk to swallowed fluticasone in pediatric EoE patients. This is a prospective, comparative effectiveness trial of newly diagnosed EoE patients (ages 2-18 years) treated with swallowed fluticasone (n = 24) or elimination of cow's milk (n = 20). The dual outcome measures of repeat esophageal biopsy (6-8 weeks) and change in Pediatric Quality of Life Inventor (PedsQL) EoE Module and Symptoms Scales were used to assess response to treatment. After 6-8 weeks of treatment, peak esophageal eosinophil counts decreased to below the threshold of 15 eosinophils/high-power field in 64% of patients treated with cow's milk elimination and 80% of patients treated with swallowed fluticasone (P = 0.4). Mean PedsQL EoE Module total scores (69 vs. 82; P < 0.005) and Total Symptoms scores (58 vs. 75; P = 0.001) showed significant improvement with cow's milk elimination. Among children treated with swallowed fluticasone, mean PedsQL EoE Module total scores (64 vs. 75; P < 0.05) and Total Symptoms scores (58 vs. 69; P < 0.01) were also significantly improved after 6-8 weeks of therapy. Removal of cow's milk from the diet is an effective single food elimination treatment for pediatric patients with EoE as assessed by statistically significant histologic and symptomatic improvement. Cow's milk elimination may be more desirable for EoE patients who do not want to take chronic, long-term steroid medications.

CD209a expression on dendritic cells is critical for the development of pathogenic Th17 cell responses in murine schistosomiasis

In murine schistosomiasis, immunopathology and cytokine production in response to parasite eggs are uneven and strain dependent. CBA/J (CBA) mice develop severe hepatic granulomatous inflammation associated with prominent Th17 cell responses driven by dendritic cell (DC)-derived IL-1β and IL-23. Such Th17 cells fail to develop in low-pathology C57BL/6 (BL/6) mice, and the reasons for these strain-specific differences in APC reactivity to eggs remain unclear. We show by gene profiling that CBA DCs display an 18-fold higher expression of the C-type lectin receptor CD209a, a murine homolog of human DC-specific ICAM-3-grabbing nonintegrin, compared with BL/6 DCs. Higher CD209a expression was observed in CBA splenic and granuloma APC subpopulations, but only DCs induced Th17 cell differentiation in response to schistosome eggs. Gene silencing in CBA DCs and overexpression in BL/6 DCs demonstrated that CD209a is essential for egg-elicited IL-1β and IL-23 production and subsequent Th17 cell development, which is associated with SRC, RAF-1, and ERK1/2 activation. These findings reveal a novel mechanism controlling the development of Th17 cell-mediated severe immunopathology in helminthic disease.

Predicting Soybean Rust Incursions into the North American Continental Interior Using Crop Monitoring, Spore Trapping, and Aerobiological Modeling

Between 2005 and 2009, millions of U.S. and Canadian soybean acres that would have received fungicide application remained untreated for soybean rust due to information disseminated through the Integrated Pest Management Pest Information Platform for Extension and Education (ipmPIPE), increasing North American producers' profits by hundreds of millions of dollars each year. The results of our analysis of Phakopsora pachyrhizi urediniospores in rain collections, aerobiology model output, and observations of soybean rust spread in 2007 and 2008 show a strong correspondence between spore collections and model predictions for the continental interior of North America, where soybean is an important crop. The analysis suggests that control practices based on up-to-date maps of soybean rust observations and associated commentary from Extension Specialists delivered by the ipmPIPE may have suppressed the number and strength of inoculum source areas in the southern states and retarded the northward progress of seasonal soybean rust incursions into continental North America. The analysis further indicates that spore trapping and aerobiological modeling can reduce our reliance on the costly Sentinel Plot Network while maintaining the effectiveness of the ipmPIPE system for soybean rust management.

The Effect of Solar Irradiance on the Mortality of Phakopsora pachyrhizi Urediniospores

Soybean rust, caused by Phakopsora pachyrhizi, may be the most important foliar disease of soybean. Within the last 10 years, the fungus has moved to many new geographical locations via spread of airborne urediniospores. The objective of this study was to determine the relationship between urediniospore viability and exposure to solar radiation. Urediniospores of P. pachyrhizi were exposed in Capitán Miranda, Paraguay, to determine the deleterious effects of sunlight. Concomitant total solar (0.285 to 2.8 μm) and ultraviolet (0.295 to 0.385 μm) irradiance measurements were used to predict urediniospore germination. Urediniospores exposed to doses of solar and ultraviolet (UV) radiation ≥27.3 MJ/m² and ≥1.2 MJ/m², respectively, did not germinate. The proportions of urediniospores that germinated, normalized with respect to the germination proportion for unexposed urediniospores from the same collections, were a linear function of solar irradiance (R² = 0.83). UV measurements predicted normalized germination proportions equally well. Results of inoculation experiments with exposed P. pachyrhizi urediniospores supported the results of the germination trials, although the effects of moderate levels of irradiance varied. The relationship between urediniospore viability and exposure to solar radiation has been incorporated into the U.S. Department of Agriculture's soybean rust aerobiological model that provides North American soybean growers with decision support for managing soybean rust.

Verification of a European corn borer (Lepidoptera: Crambidae) loss equation in the major corn production region of the northeastern United States

Field studies in Pennsylvania and Maryland were conducted during 2000, 2001, and 2002 to test the applicability of published yield loss relationships developed in central Pennsylvania for European corn borer, Ostrinia nubilalis (Hübner), management in warmer, longer season corn, Zea mays L., grain production regions of the northeastern United States. Both isoline hybrids and non-Bt lead hybrids were compared against Bacillus thuringiensis (Bt) hybrids to measure effects of the pest on yield. The European corn borer economic analysis model was used to make site-specific predictions of loss per European corn borer larva for comparison with measured yield loss per larva. Although the model did not predict loss per larva at a field level, it did predict loss at a regional level. The model predicted an overall percentage of yield loss per larva of 2.69+/-0.12% over the region, which was similar to the measured yield loss per larva of 2.66+/-0.59% for isoline hybrids and 3.08+/-0.51% for lead hybrids. The model, on average, provided a good prediction of percentage of yield loss per larva within the climatic zones of 1100-1700 degree-days (DD) (base threshold 12.5 degrees C). Our results suggest that the yield loss relationship developed in Central Pennsylvania, when matched to the timing of third instar second generation European corn borer stalk tunneling is adequate for major corn grain production zones of the northeast United States.

Estimating disease risk at the whole plant level with General Circulation Models

General Circulation Models (GCMs) have been developed to assess the impacts of potential global climate change. However, these models do not provide specific weather information at the whole-plant level and thus provide only very gross estimates of conditions that affect plant and disease development. Also, climatic change may increase the frequency of extreme events that influence plant production more than changes in daily or monthly averages. One solution is a simulation approach that can scale weather information from the global down to the plant scale. Over the last 4 years, we have been developing methods to hierarchically define current and forecast weather conditions down to the whole-plant level based on nested high-resolution atmospheric (mesoscale) numerical models. Two hierarchical mesoscale model approaches were tested to downscale weather data in a vineyard. The first, known as the Localized Mesoscale Forecast System (LMFS) uses surface databases to 'localize' mesoscale output. The second, known as the Canopy-Mesoscale Forecast System (CMFS), uses a boundary layer model to downscale mesoscale output. To illustrate the utility of this approach we focused on surface wetness duration (SWD), a variable with high spatial and temporal variability. SWD is also a critical variable for prediction of plant disease. Simulations of SWD with on-site input data were compared to those derived from the mesoscale models and to on-site sensors. Forecasts of atmospheric variables by the two systems were compared to on-site observations. Success in this effort leads us to extend this method to GCMs where factors such as temperature, rainfall, relative humidity, and surface wetness can be estimated within plant and crop canopies. We explore the implications of this work on evaluating the assessment of climate change on the risk of plant disease development.

Evaluation of postural stability in workers exposed to lead at a secondary lead smelter

Postural sway testing was carried out on a group of 145 workers exposed to lead in a secondary lead smelter and 84 workers not exposed to lead in a hinge manufacturing plant. All workers were measured for blood lead levels (BLL) and erythrocyte zinc protoporphyrin (ZPP) concentrations at the time of testing and both a total cumulative and a time-weighted average BLL value was constructed for the lead exposed workers. The lead exposed workers mean BLL at the time of testing was 38.9 microg/dl and the non-exposed workers mean was 2.3 microg/dl. ZPP levels averaged 55.2 microg/dl for exposed workers and 18.9 microg/dl for non-exposed workers. Total cumulative BLL averaged 83476 microg/dl days for the exposed workers, with a mean time-weighted average BLL of 35.1 microg/dl. Six tests of postural stability, four two leg conditions and two single leg conditions were administered to all subjects using a force platform to produce measurements of sway for comparison purposes. The two leg conditions also manipulated the visual and proprioceptive systems. A statistically significant association was observed for sway measurements and the current BLL for all workers, but not with the current BLL of only the lead exposed workers. No statistically significant associations were present with the cumulative measures of long-term exposure. Of the six tests of sway, only the single leg conditions showed significant exposure effects. The results suggest effects of lead exposure among those with average BLL near 40.0 microg/dl, but only in the most challenging one leg conditions.

Neurophysiological and neuropathological evaluation of primates exposed to ethylene oxide and propylene oxide

Over 500,000 workers in the United States are exposed to ethylene oxide and propylene oxide. These two solvents are used as chemical intermediates, as well as components in the manufacture of fumigants and food preparation. The neurophysiologic and neuropathologic effects of these two organic oxides were investigated in five groups of 12 primates after exposure to 50 or 100 ppm ethylene oxide, 100 or 300 ppm propylene oxide, or no chemical (sham-exposed). Animals were exposed for 7 h/day, 5 days/wk for 24 months. Body weights, electroencephalograms, and motor nerve conduction velocities of the sciatic and ulnar nerves were assessed six times throughout the exposure period. Although the monkeys exposed to 100 ppm ethylene oxide had significantly lower mean weights, nerve conduction velocities did not differ significantly among the groups. Following termination of exposures, ten animals (two from each exposure group) were sacrificed for neuropathological examinations. Multiple axonal bodies were found in the nucleus gracilis in seven of eight oxide-exposed animals, and demyelination was found in two monkeys exposed to ethylene oxide. In contrast, a single axonal body was found in one of the two sham-control monkeys. However, the lack of a dose-response relationship suggests that this effect may not be related to oxide exposure. In a follow-up study, nerve conduction velocity and neuropathology were assessed in the remaining monkeys seven years after exposure terminated, but again, treatment-related effects could not be detected.

A mathematical model of performance on a simple reaction time test

A nonlinear function with components for learning and fatigue was used to model individual performance on a simple reaction time test. The relationships between the parameters of the model and the mean and variance of the reaction times are discussed. The function is used to analyze data from a field study of agricultural workers exposed to organophosphate pesticides. Exposure had a significant effect on the relationships between education level and initial performance, age and fatigue rate, and age and performance variability. Parameter estimates from the model were able to distinguish between effects that the mean and standard deviation of the reaction times were unable to distinguish.

Evaluating unlicensed assistive personnel models. Asking the right questions, collecting the right data

Although the popularity of unlicensed assistive personnel (UAP) models is evident by their implementation across the country, there has been very little scientifically based evaluation of their effectiveness. To facilitate better program evaluation, the authors review the current literature and outline a variety of data elements essential to effective UAP model evaluation. Major concepts that are addressed include program cost-effectiveness, customer satisfaction, patient outcomes, and evaluation of the success of both the training and implementation processes. Research questions that are pertinent to the model and need investigation also are presented. It is only through more thorough program evaluations that nurse executives can make informed decisions regarding the outcomes of care delivery restructuring efforts.

Neurobehavioral test methods for environmental health studies of adults

The Agency for Toxic Substances and Disease Registry convened a workshop in Atlanta, GA, that evaluated approaches and methods to ascertain whether there are neurobehavioral sequelae to children and adults exposed to hazardous substances in the environment. This article, developed from that Workshop, recommends testing methods [to identify neurotoxic insult] for immediate use in environmental health field studies of adults. A list of broad functional domains or modalities affected by chemicals was identified from the occupational and related literature (learning and memory, coding, sustained attention, higher intellectual function, strength, coordination, speed, vision, somatosensory, and affect). A core set of tests was selected that should assess those functions with the greatest demonstrated sensitivity to established neurotoxic chemicals, and a secondary set was selected to assess a broader group of functions. The core tests should be used in all investigations where neurotoxic effects would be targeted for identification; secondary tests would be used where suggested by questionnaire or symptom data or by knowledge of the effects of chemicals at the hazardous waste site.

The University Hospital Nurse Extender Model. Part II, Program implementation

This second article in a four-part series provides a detailed discussion of each phase of the implementation process, along with a demographic summary of the University Hospital Patient Care Technicians' Program 2 years after program implementation. Part I provided the overview and conceptual framework for the model. Parts III and IV will present the results of a year-long evaluation of the model and the lessons learned during the implementation process.

Wound healing. Oral and topical activity of Aloe vera

The influence of Aloe vera, orally and topically, on wound healing was studied. Wounds were induced on both sides of the vertebral column of ICR mice using a biopsy punch. For the oral study, experimental animals received A. vera in their drinking water for 2 months, whereas the control animals received only water. In the topical study, experimental animals were given 25% A. vera in Eucerin cream topically. The control animals received cream only. A 62.5% reduction in wound diameter was noted in mice receiving 100 mg/kg/day oral A. vera and a 50.8% reduction was recorded in animals receiving topical 25% A. vera. These data suggest that A. vera is effective by both oral and topical routes of administration.

Anti-inflammatory activity of Aloe vera against a spectrum of irritants

The authors have evaluated the spectrum of anti-inflammatory activity of A. vera in a number of models of inflammation in the hind paw of the experimental rat induced by kaolin, carrageenan, albumin, dextran, gelatin, and mustard. Croton oil was used in a topical model of inflammation to determine the oral activity and time-dependent dosing of A. vera. The authors found that A. vera was active in all models of inflammation. Of the various irritants tested, A. vera was especially active against gelatin-induced and kaolin-induced edema and, in contrast, had minimal activity when tested against dextran-induced edema. Oral activity of A. vera was demonstrated to be dependent on the presence of anthraquinones. The various irritant-induced edema models provided a broad spectrum of anti-inflammatory activity for A. vera.

Neurobehavioral assessment of chronic low-level methyl bromide exposure in the rabbit

The research reported here was intended to identify the concentration at which methyl bromide begins to produce neurotoxic effects in the rabbit, a species known to be sensitive to this compound. Rabbits were exposed via inhalation to 27 ppm methyl bromide over a period of 8 mo for a total exposure duration of 900 h. Biweekly neurobehavioral tests, consisting of the latency rates of the ulnar and sciatic nerves and the amplitude of the eyeblink reflex of the orbicularis oculi muscle, failed to uncover any untoward consequences of the exposures. The rabbits gained weight and otherwise appeared to be healthy. In contrast to reports available in the literature, these findings suggest that long-term exposures to methyl bromide, in the present concentration range, are tolerated by this species. Also detailed in this report is the course of recovery of a separate group of rabbits previously given subchronic exposures to 65 ppm methyl bromide. These animals developed severe neuromuscular losses and had impaired blink reflexes and body weights. The symptoms partially subsided within 6-8 wk after removal from the exposures, suggesting that recovery from a nonfatal but seriously debilitating exposure is possible.

Combination rules for inhibitory stimuli

Startle reactions are inhibited if their elicitation is preceded by weak neutral stimuli at lead times of fractions of a second, or by intense startle-eliciting stimuli at lead times of up to several seconds. In three experiments (a) two weak stimuli, (b) one weak stimulus and one intense stimulus, or (c) two strong stimuli were given in combination. In all three conditions the combination provided more response inhibition than did either stimulus alone. Conditions 1 and 2 gave combination effects in which the inhibited proportion of the response was described by the rule for compounding the probabilities of independent events, indicating that the stimuli had noncompetitive independent access to the inhibitory machinery. The rule over-estimated the effect of the compound in Condition c, suggesting the presence of some other summative process, perhaps involving the prolongation of the refractory period.

Combination rules for inhibitory stimuli

Startle reactions are inhibited if their elicitation is preceded by weak neutral stimuli at lead times of fractions of a second, or by intense startle-eliciting stimuli at lead times of up to several seconds. In three experiments (a) two weak stimuli, (b) one weak stimulus and one intense stimulus, or (c) two strong stimuli were given in combination. In all three conditions the combination provided more response inhibition than did either stimulus alone. Conditions 1 and 2 gave combination effects in which the inhibited proportion of the response was described by the rule for compounding the probabilities of independent events, indicating that the stimuli had noncompetitive independent access to the inhibitory machinery. The rule over-estimated the effect of the compound in Condition c, suggesting the presence of some other summative process, perhaps involving the prolongation of the refractory period.