University of Kentucky

About: University of Kentucky is a education organization based out in Lexington, Kentucky, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 43933 authors who have published 92195 publications receiving 3256087 citations. The organization is also known as: UK.

Eicosapentaenoic acid prevents LPS-induced TNF-alpha expression by preventing NF-kappaB activation.

Abstract: Background: Many studies have shown that fish oil supplementation inhibits tumor necrosis factor-α (TNF-α) production in mice and human subjects; however, the mechanisms remain unclear. Nuclear factor-κB (NF-κB) is a transcription factor that plays an important role in controlling the expression of pro-inflammatory genes including TNF-α. Activation of NF-κB has been shown to mediate the maximal expression of TNF-α in human monocytes. NF-κB is kept in an inactive form in the cytoplasm by IκB, the inhibitory subunit of NF-κB complex. Phosphorylation and subsequent degradation of IκB lead to NF-κB activation.Objectives: The effect of eicosapentaenoic acid (EPA), a major n-3 fatty acid in fish oil, on the lipopolysaccharide (LPS)-induced expression of TNF-α and activation of NF-κB were investigated. The mechanism underlying EPA modulation of NF-κB activation was also studied.Methods: Human monocytic THP-1 cells were pre-incubated with EPA and stimulated with LPS. The levels of secreted TNF-α were determined b...

Can altruism evolve in purely viscous populations

Abstract: Limited dispersal is often thought to facilitate the evolution of altruism by increasing the degree of relatedness among interacting individuals Limited dispersal can have additional effects, however, such as local population regulation, that inhibits the evolution of altruism Many models of structured populations assume that a viscous stage of the life cycle alternates with a global mixing stage, which allows the advantages of interactions among close relatives without the disadvantages of local population regulation Here we analyse a computer simulation model of ‘pure’ population viscosity, in which offspring are always deposited close to parents and no global mixing stage exists As expected, limited dispersal generates a high coefficient of relatedness among interacting individuals Patches of altruists, however, are unable to ‘export’ their productivity to other regions of the landscape and are easily invaded by selfish types from neighbouring patches Unlike models of alternating viscosity, in which high relatedness and local population regulation can be decoupled, these two opposing effects are inextricably linked in purely viscous populations, which therefore are not conducive to the evolution of altruistic traits

Prospective multicenter study of thyroid carcinoma treatment initial analysis of staging and outcome

Abstract: BACKGROUND A novel prognostic staging classification encompassing all forms of thyroid carcinoma was created for the National Thyroid Cancer Treatment Cooperative Study (NTCTCS) Registry, with the goal of prospective validation and comparison with other available staging classifications. METHODS Patient information was recorded prospectively from 14 institutions. Clinicopathologic staging was based on patient age at diagnosis, tumor histology, tumor size, intrathyroidal multifocality, extraglandular invasion, metastases, and tumor differentiation. RESULTS Between 1987 and 1995, 1607 patients were registered. Approximately 43% of patients were classified as NTCTCS Stage I, 24% Stage II, 24% Stage III, and 9% Stage IV. Patients with follicular carcinoma were more likely to have "high risk" Stage III or IV disease than those with papillary carcinoma. Of 1562 patients for whom censored follow-up was available (median follow-up, 40 months), 78 died of thyroid carcinoma or complications of its treatment. Five-year product-limit patient disease specific survival was 99.8% for Stage I, 100% for Stage II, 91.9% for Stage III, and 48.9% for Stage IV (P < 0.0001). The frequency of remaining disease free also declined significantly with increasing stage (94.3% for Stage I, 93.1% for Stage II, 77.8% for Stage III, and 24.6% for Stage IV). The same patients also were staged applying six previously published classifications as appropriate for their tumor type. The predictive value of the NTCTCS Registry staging classification consistently was among the highest for disease specific mortality and for remaining disease free, regardless of the tumor type. Conclusions The NTCTCS Registry staging classification provides a prospectively validated scheme for predicting short term prognosis for patients with thyroid carcinoma. [See editorial counterpoint on pages 844-7 and reply to counterpoint on pages 848-50, this issue.] Cancer 1998;83:1012-1021. © 1998 American Cancer Society.

Eliciting willingness to pay without bias: evidence from a field experiment*

Abstract: Concern exists that hypothetical willingness to pay questions overestimate real willingness to pay In a field experiment, we compare two methods of removing hypothetical bias, a cheap talk approach and a certainty approach, with real purchases We find evidence of hypothetical bias for unadulterated contingent valuation Contingent valuation with certainty statements removes the hypothetical bias, but the cheap talk approach has no significant impact Our findings suggest that willingness to pay can be accurately estimated by adding a simple follow-up question about the certainty of responses and that cheap talk is not a generally effective approach Information about the willingness to pay for non-market goods is crucial for understanding the welfare implications of different policies Ideally we would like to rely on actual choices for inferring willingness to pay But for many public programmes, especially those in the environmental and health area, revealed preference information is limited This limitation can arise from the lack of markets or third-party financing Researchers have therefore tried to estimate willingness to pay based on stated preferences that are hypothetical choices This methodology, known as contingent valuation, typically involves a survey or experiment in which there is a detailed description of the good being offered, a description of how the good would be provided, a method for eliciting preferences for the good, follow up debriefing questions and questions about socioeconomic characteristics (Portney, 1994; Carson, 2001) Contingent valuation is still somewhat controversial in economics (Diamond and Hausman, 1994; Carson et al,

Green Tea Polyphenols Block Endotoxin-Induced Tumor Necrosis Factor-Production and Lethality in a Murine Model

Abstract: Green tea polyphenols are potent antioxidants. They have both anti-cancer and anti-inflammatory effects. However, their mechanisms of actions remain unclear. In inflammation, tumor necrosis factor-alpha(TNFalpha) plays a pivotal role. NF-KB, an oxidative stress -sensitive nuclear transcription factor, controls the expression of many genes including the TNFalpha gene. We postulated that green tea polyphenols regulate TNFalpha gene expression by modulating NF-KB activation through their antioxidant properties. In the macrophage cell line, RAW264.7, (-)epigallocatechin gallate (EGCG), the major green tea polyphenol, decreased lipopolysaccharide (LPS)-induced TNFalpha production in a dose-dependent fashion (50% inhibition at 100 mmol/L). EGCG also inhibited LPS-induced TNFalpha mRNA expression and nuclear NF-KB-binding activity in RAW264.7 cells (30-40% inhibition at 100 mmol/L). Similarly, EGCG inhibited LPS-induced TNFalpha production in elicited mouse peritoneal macrophages. In male BALB/c mice, green tea polyphenols (given by oral gavage 2 h prior to an i.p. injection of 40 mg LPS/kg body wt) decreased LPS-induced TNFalpha production in serum in a dose-responsive fashion. At a dose of 0.5 g green tea polyphenols/kg body wt, serum TNFalpha was reduced by 80% of control. Moreover, 0.5 g green tea polyphenols/kg body wt completely inhibited LPS-induced lethality in male BALB/c mice. We conclude that the anti-inflammatory mechanism of green tea polyphenols is mediated at least in part through down-regulation of TNFalpha gene expression by blocking NF-KB activation. These findings suggest that green tea polyphenols may be effective therapy for a variety of inflammatory processes.