Inflammatory Effect of Intradermal Administration of Soluble Phospholipase A2 in Rabbits

Extracellular phospholipase A2 (PLA2) has been found in association with inflamed sites in experimental animals and in humans. The tissue effects of soluble PLA2 have not been defined. We studied the development of inflammatory changes in rabbit skin subsequent to intradermal injection of active and inactivated venom and pancreatic PLA2, over a broad concentration range. PLA2, at concentrations encountered in human disease, caused acute inflammatory changes characterized grossly by erythema and induration, and histologically by inflammatory cell infiltration vascular and tissue damage, and abscess formation. Extracellular PLA2 may be considered as one of the pathogenic factors in inflammatory reaction

Peanut Allergy: An Overview

<p/> <p>Peanut allergies have been increasing in prevalence in most industrialized countries. Onset is typically in early childhood, with a trend towards earlier ages of presentation. The allergy is lifelong in most affected children, although 15-22% will outgrow their peanut allergy, usually before their teenage years. Manifestations of peanut allergy range from mild to severe, and risk factors predisposing to severe reactions are discussed. However, even in the absence of risk factors, peanut allergic individuals may still experience life-threatening anaphylactic reactions. Approaches to investigation and treatment, patterns of cross-reactivity and possible causes of rising prevalence are discussed.</p

Induction of circulating phospholipase A2 by intravenous administration of recombinant human tumour necrosis factor

We have examined the effects of intravenous infusion of recombinant human tumour necrosis factor (rh-TNF) on serum activity of phospholipase A2 (PLA2) in patients with malignancies. Nine patients received a 24 h continuous intravenous infusion ranging from 1.0 × 105 U/m2 to 3.0 × 105 U/m2; 14 patients received a 5 day continuous intravenous infusion ranging from 0.5 × 105 U/m2/day to 3.0 105 U/m2/day. Twenty one of 23 patients responded with marked increases in serum PLA2 activity that were detectable 3 h after the beginning of the rh-TNF infusion and reached maximum levels at 18 h with a mean increase of 16.2-fold. In patients receiving a 5 day rh-TNF infusion, the highest levels of PLA2 were observed after the first day of infusion. Serum PLA2 activity declined continuously to 2.9-fold above baseline at the end of the infusion. A significant correlation was noted between the dose of infused rh-TNF and the maximum increase in PLA2 activity. To our knowledge, this is the first time that an association between intravenous TNF administration and induction of circulating PLA2 in man has been established

Exploring Agricultural Production Systems and Their Fundamental Components with System Dynamics Modelling

Agricultural production in the United States is undergoing marked changes due to rapid shifts in consumer demands, input costs, and concerns for food safety and environmental impact. Agricultural production systems are comprised of multidimensional components and drivers that interact in complex ways to influence production sustainability. In a mixed-methods approach, we combine qualitative and quantitative data to develop and simulate a system dynamics model that explores the systemic interaction of these drivers on the economic, environmental and social sustainability of agricultural production. We then use this model to evaluate the role of each driver in determining the differences in sustainability between three distinct production systems: crops only, livestock only, and an integrated crops and livestock system. The result from these modelling efforts found that the greatest potential for sustainability existed with the crops only production system. While this study presents a stand-alone contribution to sector knowledge and practice, it encourages future research in this sector that employs similar systems-based methods to enable more sustainable practices and policies within agricultural production

Manure Application Timing Drives Energy Absorption for Snowmelt on an Agricultural Soil

Reducing agricultural runoff year-round is important, in particular during snowmelt events on landscapes that receive wintertime applications of manure. To help inform manure guidelines, process-level data are needed that link management scenarios with the complexity of snowmelt, hence runoff. Albedo and radiative energy fluxes are strong drivers of thaw, but applying these mechanistic measurements across multiple, plot-scale management treatments over time presents a logistical challenge. The objective of this study was to first develop a practical field approach to estimate winter albedo in plot-scale field research with multiple management scenarios. The second objective was to quantify the radiative drivers of snowmelt by measuring fluxes after wintertime liquid manure application. Six management treatments were tested in south-central Wisconsin during the winters of 2015–2016 and 2016–2017 with a complete factorial design: three manure application timings (early December, late January, and unmanured) and two tillage treatments (conventional tillage versus no-tillage). A multiple linear regression model was developed to estimate albedo with digital imagery and readily-obtained site characteristics. Manure timing had a significant effect on radiative energy fluxes and tillage was secondary. January applications of liquid manure produced an immediate and lasting decrease in albedo, which resulted in greater net radiation absorbed by snowpack and subsequent energy available for snowmelt. Later applications of liquid manure accelerated snowmelt, which increased runoff losses and posed a challenge for nutrient retention from the liquid manure during thaw

Use of Annual Phosphorus Loss Estimator (APLE) Model to Evaluate a Phosphorus Index

The Phosphorus (P) Index was developed to provide a relative ranking of agricultural fields according to their potential for P loss to surface water. Recent efforts have focused on updating and evaluating P Indices against measured or modeled P loss data to ensure agreement in magnitude and direction. Following a recently published method, we modified the Maryland P Site Index (MD-PSI) from a multiplicative to a component index structure and evaluated the MD-PSI outputs against P loss data estimated by the Annual P Loss Estimator (APLE) model, a validated, field-scale, annual P loss model. We created a theoretical dataset of fields to represent Maryland conditions and scenarios and created an empirical dataset of soil samples and management characteristics from across the state. Through the evaluation process, we modified a number of variables within the MD-PSI and calculated weighting coefficients for each P loss component. We have demonstrated that our methods can be used to modify a P Index and increase correlation between P Index output and modeled P loss data. The methods presented here can be easily applied in other states where there is motivation to update an existing P Index

Linking Nutrient Transport to Soil Physical Processes During Freeze/Thaw Events to Promote Wintertime Manure Management, Nutrient Use Efficiency, and Surface Water Quality.

The application of dairy manure to the landscape during winter is a longstanding practice for farms in the Midwestern United States and other temperate regions. Practical motivations behind winter spreading include affordability, availability of time, and the reduced risk of compaction from farm equipment on frozen soils. Wintertime manure applications, however, coincide with environmental conditions that are prone to runoff and accelerate nutrient losses from agricultural fields. Understanding the nutrient dynamics in response to winter-applied manure is especially important to Wisconsin, a leading state in dairy production, where up to 75% of annual runoff volumes occur on frozen and thawing soils. The high potential for winter runoff, hence nutrient transport, has prompted revisions to winter manure regulations, yet little conclusive data exist to guide these changing standards

Temperature and Manure Placement in a Snowpack Affect Nutrient Release from Dairy Manure During Snowmelt

Agricultural nutrient management is an issue due to N and P losses from fields and water quality degradation. Better information is needed on the risk of nutrient loss in runoff from dairy manure applied in winter. We investigated the effect of temperature on nutrient release from liquid and semisolid manure to water, and of manure quantity and placement within a snowpack on nutrient release to melting snow. Temperature did not affect manure P and NH4–N release during water extraction. Manure P release, but not NH4–N release, was significantly influenced by the water/manure solids extraction ratio. During snowmelt, manure P release was not significantly affected by manure placement in the snowpack, and the rate of P release decreased as application rate increased. Water extraction data can reliably estimate P release from manure during snowmelt; however, snowmelt water interaction with manure of greater solids content and subsequent P release appears incomplete compared with liquid manures. Manure NH4–N released during snowmelt was statistically the same regardless of application rate. For the semisolid manure, NH4–N released during snowmelt increased with the depth of snow covering it, most likely due to reduced NH3 volatilization. For the liquid manure, there was no effect of manure placement within the snowpack on NH4–N released during snowmelt. Water extraction data can also reliably estimate manure NH4–N release during snowmelt as long as NH3 volatilization is accounted for with liquid manures for all placements in a snowpack and semisolid manures applied on top of snow