Iron induces insulin resistance in cardiomyocytes via regulation of oxidative stress

York University Librarie

Adiponectin Action: A Combination of Endocrine and Autocrine/Paracrine Effects

The widespread physiological actions of adiponectin have now been well characterized as clinical studies and works in animal models have established strong correlations between circulating adiponectin level and various disease-related outcomes. Thus, conventional thinking attributes many of adiponectin’s beneficial effects to endocrine actions of adipose-derived adiponectin. However, it is now clear that several tissues can themselves produce adiponectin and there is growing evidence that locally produced adiponectin can mediate functionally important autocrine or paracrine effects. In this review article we discuss regulation of adiponectin production, its mechanism of action via receptor isoforms and signaling pathways, and its principal physiological effects (i.e., metabolic and cardiovascular). The role of endocrine actions of adiponectin and changes in local production of adiponectin or its receptors in whole body physiology is discussed

Protein Kinase C Isoforms: Insulin Signalling, Cyclic AMP Metabolism and Diabetes

Protein kinase C has been implicated in the regulation of insulin signalling by many previous studies. This phenomenon was further investigated here using both established and novel experimental systems. Using the streptozotocin-induced diabetic rat model, protein kinase C activity was assessed after partial purification of the enzyme from the liver of both normal and diabetic rats. It was found that inducing diabetes in rats using streptozotocin resulted in a decrease in total protein kinase C activity. Further analysis of protein kinase C activity showed that this difference was accounted for both by a reduction in activity of Ca2+-dependent and Ca2+-independent isoforms. To enable correlation of protein kinase C isoform expression with activity changes in these samples, antibodies were raised to specifically detect individual protein kinase C isoforms. Results from immunoblotting studies using isoform specific antisera suggested that, in rat liver, the reduced Ca2+-dependent protein kinase C activity might be associated with alterations in the alpha and betaII isoforms, whilst modified activity of the PKC-epsilon species may have been responsible for the reduced Ca2+-independent activity observed. The availability of a set of Chinese hamster ovary cell clones overexpressing the human insulin receptor, both alone and combined with a specific protein kinase C isoform, allowed direct in vitro analysis of the interaction of insulin and protein kinase C. In this case their control of intracellular cyclic AMP metabolism was studied. Results obtained by directly measuring intracellular cyclic AMP concentration in cells suggest that insulin can attenuate agonist stimulated increases in intracellular cyclic AMP concentration. However, this effect of insulin was only evident in cells overexpressing both the human insulin receptor and PKC-epsilon (CHO-epsilon cells). Upon directly measuring cyclic AMP phosphodiesterase activity in all CHO cell clones available, it was observed that CHO-epsilon cells exhibited a higher basal phosphodiesterase activity than any other cell clone and that this activity was substantially increased by treating cells with insulin. Both of these observations were no longer apparent after cells had undergone long-term phorbol ester treatment to down-regulate protein kinase C. These results confirmed that PKC-epsilon plays a crucial role in regulating both basal phosphodiesterase activity and insulin induced changes in phosphodiesterase activity within these cells. They also suggested that insulin's ability to attenuate agonist induced increases in intracellular cyclic AMP concentrations in these cells was due, at least partly, to stimulation of cyclic AMP phosphodiesterase activity

Response of Soybean Grown on a Claypan Soil in Southeastern Kansas to the Residual of Different Plant Nutrient Sources and Tillage

The residual from previous high rate turkey litter applications, which were based on N requirements of the previous grain sorghum crop, increased soybean yield above that obtained from the residual of P-based turkey litter applications (low rate), commercial fertilizer, or the control. Even though early soybean growth was not significantly affected by residual treatments, the greatest dry matter production at the R6 growth stage was where the N-based litter had been applied and incorporated

Surface Runoff Characteristics from Claypan Soil in Southeastern Kansas Receiving Different Plant Nutrient Sources and Tillage

Preliminary results show that two-year average total nitrogen (N) runoff losses and ortho-phosphorus (P) and total P runoff losses in the second year were greater with N-based turkey litter/no-till applications than P-based turkey litter or fertilizer-only applications. Incorporation of turkey litter applied based on N requirements resulted in N and P losses that did not differ from losses from P-based or fertilizer-only treatments. Chemical and statistical analyses of third-year samples will allow for final results and interpretation

Response of Soybean Grown on a Claypan Soil in Southeastern Kansas to the Residual of Different Plant Nutrient Sources and Tillage

The residual from previous high rate turkey litter applications, which were based on N requirements of the previous grain sorghum crop, increased soybean yield above that obtained from the residual of P-based turkey litter applications (low rate), commercial fertilizer, or the control. Even though early soybean growth was not significantly affected by residual treatments, the greatest dry matter production at the R6 growth stage was where the N-based litter had been applied and incorporated

Response of Soybean Grown on a Claypan Soil in Southeastern Kansas to the Residual of Different Plant Nutrient Sources and Tillage

Soybean yields measured from 2014 through 2016 were more than 50% greater from the residual from N-based turkey litter applications during 2011 through 2013 than in the control where no nitrogen (N) or phosphorus (P) was applied. However, residual from P-based turkey litter applications or fertilizer-only did not result in soybean yield different from the no N-P control. This residual effect on yield was largely due to increased pods per plant

Submarine Pier Side Weapons Handling Risk Assessment

Dr. Warren Vaneman, Prof. Joseph Sweeney, Dr. Gary Langford, Mr. Gary Parker, Mr. Chris Wolfgeher, LCDR Willima HarleyThis research examines new methods to assess and improve Physical Protection Systems (PPS), paying specific attention to a Navy Level 3 Restricted Areas, a special type of industrial and refit zone that normally handles high value units such as aircraft carriers and ballistic missile submarines, utilizing Model Based Systems Engineering (MBSE) and System of Systems (SoS) theory to create a framework which couples architectural level PPS design with detailed discrete event security assessment and prediction techniques in order to provide decision makers and acquisition authorities a more quantitative and effective method to holistically understand a PPS and the PPS�s internal and external interactions, allowing for improved capability and vulnerability analysis and the formulation of sound acquisition decisions.Naval Research ProgramPrepared for: Navy Strategic Systems Program (SSP) Sponsor: Mr. Brent Flaskerud, SP3015, Nuclear Weapon Security (NWS) Modeling and Simulation (M&S) and Demonstration

Response of Soybean Grown on a Claypan Soil in Southeastern Kansas to the Residual of Different Plant Nutrient Sources and Tillage

Increased fertilizer prices in recent years, especially noticeable when the cost of phosphorus spiked in 2008, have led U.S. producers to consider other alternatives, including manure sources. The use of poultry litter as an alternative to fertilizer is of particular interest in southeastern Kansas because large amounts of poultry litter are imported from nearby confined animal feeding operations in Arkansas, Oklahoma, and Missouri. Annual application of turkey litter can affect the current crop, but information is lacking concerning any residual effects from several continuous years of poultry litter applications on a following crop. This is especially true for tilled soil compared with no-till because production of most annual cereal crops on the claypan soils of the region is often negatively affected by no-till planting. The objective of this study was to determine if the residual from fertilizer and poultry litter applications under tilled or no-till systems affects soybean yield and growth