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Search Results: 1 - 10 of 248831 matches for " Keith R. Martin "
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Comparison of Sensory Qualities of Geographically Paired Organic and Conventional Red Wines from the Southwestern US with Differing Total Polyphenol Concentrations: A Randomized Pilot Study  [PDF]
Keith R. Martin, Kristen K. Rasmussen
Food and Nutrition Sciences (FNS) , 2011, DOI: 10.4236/fns.2011.210154
Abstract: Dietary polyphenols, or phenolic compounds, are numerous, diverse, and ubiquitous phytochemicals occurring throughout the plant kingdom. They are important components of the human diet because of their capacity to reduce the risk of chronic diseases such as cardiovascular disease and cancer. In plants, polyphenols contribute to resistance to pathogens due to their potent astringency and function as phytoalexins. As a result, organic grapevines grown with reduced pesticides may be more stressed by pathogens than conventionally grown grapevines and presumably produce more polyphenols. Since polyphenols also play an important role in the sensory qualities of fruits and wines particularly involving astringency and bitterness, there may be differences that affect sensory perceptions of wine. This establishes a conundrum where dietary polyphenols are healthful but potentially unpalatable.We recruited and randomized 18 female participants (21 - 50 y) to one of five groups (3 - 4 per group). Each group evaluated the sensory qualities of a geographically paired organic (OW) and conventional wine (CW) and an artificially colored white wine placebo (PW) with significantly differing total polyphenol concentrations (TP). Participants reported for three visits (one wine per visit) where they consumed 5 ounces (150 mL) of wine over 15 minutes while completing the sensory survey. Sensory evaluations based on a Likert-type scale included visual, aroma, and taste perceptions and overall impressions (scale 0 - 10). In two wine pairs, the OW contained significantly more TP (3.49 and 5.86 g/L) than the respective CW (2.63 and 4.63 g/L). In two other wine pairs both produced by sustainable viticulture, the CW (5.23 and 8.38 g/L) contained sig- nificantly more TP than OW (4.55 and 3.70 g/L) and in one set the amounts were equivalent (4.10 and 4.17 g/L). The five PW averaged 1.26 ± 0.20 g/L. Although there were significant differences in TP content of test wines, the results indicated that no significant differences in either intensity or quality for any of the sensory qualities were detected be- tween paired OW and CW wines but both scored significantly higher than the PW, with significantly lower TP. We conclude in this pilot study that a subset of OW from the Southwestern US is perceived similarly to CW produced by the same vineyard even with significantly differing TP concentrations.
Both common and specialty mushrooms inhibit adhesion molecule expression and in vitro binding of monocytes to human aortic endothelial cells in a pro-inflammatory environment
Keith R Martin
Nutrition Journal , 2010, DOI: 10.1186/1475-2891-9-29
Abstract: Human aortic endothelial cells (HAEC) were incubated overnight with control media with dimethylsulfoxide (DMSO) vehicle (1% v/v) or containing DMSO extracts of whole dehydrated mushrooms (0.1 mg/mL), which included Agaricus bisporus (white button and crimini), Lentinula edodes (shiitake), Pleurotus ostreatus (oyster), and Grifola frondosa (maitake). Monolayers were subsequently washed and incubated with medium alone or containing the pro-inflammatory cytokine IL-1β (5 ng/mL) for 6 h to upregulate pro-atherosclerotic adhesion molecules (AM). AM expression was assayed by ELISA and binding of U937 human monocytes pre-loaded with fluorescent dye was determined.White button mushrooms consistently reduced (p < 0.05) VCAM-1, ICAM-1, and E-selectin-1 expression, whereas other test mushrooms significantly modulated AM expression singly, collectively, or combinatorially. All mushrooms, however, significantly reduced binding of monocytes to both quiescent and cytokine-stimulated monolayers.These data provide evidence that dietary mushrooms can inhibit cellular processes such as adhesion molecule expression and ultimate binding of monocytes to the endothelium under pro-inflammatory conditions, which are associated with CVD. As a result, these findings support the notion that dietary mushrooms can be protective against CVD.Cardiovascular disease (CVD) is a leading cause of morbidity and mortality in the United States as well as globally in both developed and developing countries [1]. Epidemiological studies show that regular consumption of plants, i.e., fruits and vegetables, is strongly and convincingly associated with a reduced risk of chronic disease including CVD [2,3]. This protection presumably occurs due to a plethora of bioactive phytochemicals that can modulate processes including the immune response, inflammation and antioxidant activity [4,5]. In addition to plants, dietary fungi, viz., mushrooms, also contain a diverse array of biologically active molecules rendering
Polyphenols as dietary supplements: A double-edged sword
Keith R Martin, Christy L Appel
Nutrition and Dietary Supplements , 2010, DOI: http://dx.doi.org/10.2147/NDS.S6422
Abstract: lyphenols as dietary supplements: A double-edged sword Review (15975) Total Article Views Authors: Keith R Martin, Christy L Appel Published Date December 2009 Volume 2010:2 Pages 1 - 12 DOI: http://dx.doi.org/10.2147/NDS.S6422 Keith R Martin, Christy L Appel Nutrition Program, Healthy Lifestyles Research Center, College of Nursing and Health Innovation, Arizona State University, Mesa, AZ, USA Abstract: Increased consumption of fruits and vegetables is associated with a lower risk of chronic disease such as cardiovascular disease, some forms of cancer, and neurodegeneration. Pro-oxidant-induced oxidative stress contributes to the pathogenesis of numerous chronic diseases and, as such, dietary antioxidants can quench and/or retard such processes. Dietary polyphenols, ie, phenolic acids and flavonoids, are a primary source of antioxidants for humans and are derived from plants including fruits, vegetables, spices, and herbs. Based on compelling evidence regarding the health effects of polyphenol-rich foods, new dietary supplements and polyphenol-rich foods are being developed for public use. Consumption of such products can increase dietary polyphenol intake and subsequently plasma concentrations beyond expected levels associated with dietary consumption and potentially confer additional health benefits. Furthermore, bioavailability can be modified to further increase absorption and ultimately plasma concentrations of polyphenols. However, the upper limit for plasma concentrations of polyphenols before the elaboration of adverse effects is unknown for many polyphenols. Moreover, a considerable amount of evidence is accumulating which supports the hypothesis that high-dose polyphenols can mechanistically cause adverse effects through pro-oxidative action. Thus, polyphenol-rich dietary supplements can potentially confer additional benefits but high-doses may elicit toxicity thereby establishing a double-edge sword in supplement use.
How safe are "safe" seats? A comparison of voluntary and compulsory voting systems
Fry,Tim R. L.; Jakee,Keith; Kenneally,Martin;
Brazilian Political Science Review (Online) , 2009,
Abstract: many observers have expressed concern that low voter turnout reflects an acute shortcoming in democratic politics. one proposed remedy, making voting compulsory, has garnered increasing attention among academics over recent years. our article focuses on some of the technical properties of compulsory voting rules (cvr) while ignoring the philosophical debate over whether voting should be an obligation or a right. using basic probability analysis, we compare a voluntary voting rule (vvr) to a compulsory one. we show that, under certain conditions, an electoral seat or district can become safer - or less competitive - with the imposition of a cvr. we also discuss some political implications of our analysis. for example, when generalized to, say, the national political system, this result implies fewer competitive seats in a cvr compared to a vvr, everything else equal. we contend that, because fewer seats will be "in play" in a cvr, cvrs should exhibit lower turnover of seats. also, political suppliers can be expected to more narrowly focus their attention - and resources - on this smaller set of competitive seats than we would expect under a vvr.
Polyphenols as dietary supplements: A double-edged sword
Keith R Martin,Christy L Appel
Nutrition and Dietary Supplements , 2009,
Abstract: Keith R Martin, Christy L AppelNutrition Program, Healthy Lifestyles Research Center, College of Nursing and Health Innovation, Arizona State University, Mesa, AZ, USAAbstract: Increased consumption of fruits and vegetables is associated with a lower risk of chronic disease such as cardiovascular disease, some forms of cancer, and neurodegeneration. Pro-oxidant-induced oxidative stress contributes to the pathogenesis of numerous chronic diseases and, as such, dietary antioxidants can quench and/or retard such processes. Dietary polyphenols, ie, phenolic acids and flavonoids, are a primary source of antioxidants for humans and are derived from plants including fruits, vegetables, spices, and herbs. Based on compelling evidence regarding the health effects of polyphenol-rich foods, new dietary supplements and polyphenol-rich foods are being developed for public use. Consumption of such products can increase dietary polyphenol intake and subsequently plasma concentrations beyond expected levels associated with dietary consumption and potentially confer additional health benefits. Furthermore, bioavailability can be modified to further increase absorption and ultimately plasma concentrations of polyphenols. However, the upper limit for plasma concentrations of polyphenols before the elaboration of adverse effects is unknown for many polyphenols. Moreover, a considerable amount of evidence is accumulating which supports the hypothesis that high-dose polyphenols can mechanistically cause adverse effects through pro-oxidative action. Thus, polyphenol-rich dietary supplements can potentially confer additional benefits but high-doses may elicit toxicity thereby establishing a double-edge sword in supplement use.Keywords: antioxidant, bioavailability, flavonoids, polyphenols, supplement
Reduced Axonal Transport and Increased Excitotoxic Retinal Ganglion Cell Degeneration in Mice Transgenic for Human Mutant P301S Tau
Natalie D. Bull, Alessandra Guidi, Michel Goedert, Keith R. Martin, Maria Grazia Spillantini
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0034724
Abstract: The effects of tau hyperphosphorylation and aggregation on axonal transport were investigated in the optic nerve of mice transgenic for human mutant P301S tau. Transport was examined using cholera toxin B tracing. Retrograde transport was reduced in transgenic mice at 3 and 5 months of age, when compared to C57/Bl6 control mice. Anterograde axonal transport was also reduced in 3-month-old transgenic mice. Mild excitotoxic injury of retinal ganglion cells resulted in greater nerve cell loss in retinas from 3- and 5-month old P301S transgenic mice, when compared to controls. In conjunction with the detection of abnormal tau in the optic nerve in human and experimental glaucoma, the present findings suggest that tau hyperphosphorylation and aggregation may constitute targets for neuroprotective therapies in glaucoma as well as tauopathies.
The burden of allergic rhinitis (AR) in Canada: perspectives of physicians and patients
Paul K Keith, Martin Desrosiers, Tina Laister, R. Robert Schellenberg, Susan Waserman
Allergy, Asthma & Clinical Immunology , 2012, DOI: 10.1186/1710-1492-8-7
Abstract: Two parallel, Canadawide structured telephone interviews surveyed 1,001 AR patients and 160 physicians in July 2006.44% of patients had experienced nasal symptoms unrelated to a cold and 20% had a physician diagnosis of AR. At screening 27% reported asthma, 15% chronic or recurrent sinusitis and 5% nasal polyps. With attacks nasal congestion and runny nose were the most bothersome symptoms. Other problems experienced were fatigue (46%), poor concentration (32%), and reduced productivity (23%). Most (77%) had not seen a physician in the past year. Physicians estimated they prescribed intranasal cortico steroids (INCS) to most AR patients (77%) consistent with guidelines but only 19% of patients had used one in the last month. Only 48% of patients were very satisfied with their current INCS. 41% of AR patients reported discontinuing their INCS with the most common reason being a perceived lack of long-lasting symptom relief (44%). 52% of patients felt that their current INCS lost effectiveness over 24 h. The most common INCS side effects included dripping down the throat, bad taste, and dryness. Most AR patients reported lifestyle limitations despite treatment (66%). 61% of patients felt that their symptoms were only somewhat controlled or poorly/not controlled during their worst month in the past year.AR symptoms are common and many patients experience inadequate control. Physicians report they commonly prescribe intranasal corticosteroids, but patient’s perceived loss of efficacy and side effects lead to their discontinuation. Persistent relief of allergic rhinitis symptoms remains a major unmet need. Better treatments and education are required.
Retinal ganglion cell survival and axon regeneration in WldS transgenic rats after optic nerve crush and lens injury
Barbara Lorber, Alessia Tassoni, Natalie D Bull, Marilita M Moschos, Keith R Martin
BMC Neuroscience , 2012, DOI: 10.1186/1471-2202-13-56
Abstract: As previously reported we found that the WldS mutation does not protect RGC bodies after optic nerve crush alone. Surprisingly, we found that WldS transgenic rats did not exhibit the enhanced RGC survival response after combined optic nerve crush and lens injury that was observed in wildtype rats. RGC axon regeneration past the optic nerve lesion site was, however, similar in WldS and wildtypes. Furthermore, activation of retinal glia, previously shown to be associated with enhanced RGC survival and axon regeneration after optic nerve crush and lens injury, was unaffected in WldS transgenic rats.RGC axon regeneration is similar between WldS transgenic and wildtype rats, but WldS transgenic rats do not exhibit enhanced RGC survival after combined optic nerve crush and lens injury suggesting that the neuroprotective effects of lens injury on RGC survival may be limited by the WldS protein.
Distinct Difference Configurations: Multihop Paths and Key Predistribution in Sensor Networks
Simon R. Blackburn,Tuvi Etzion,Keith M. Martin,Maura B. Paterson
Mathematics , 2008,
Abstract: A distinct difference configuration is a set of points in $\mathbb{Z}^2$ with the property that the vectors (\emph{difference vectors}) connecting any two of the points are all distinct. Many specific examples of these configurations have been previously studied: the class of distinct difference configurations includes both Costas arrays and sonar sequences, for example. Motivated by an application of these structures in key predistribution for wireless sensor networks, we define the $k$-hop coverage of a distinct difference configuration to be the number of distinct vectors that can be expressed as the sum of $k$ or fewer difference vectors. This is an important parameter when distinct difference configurations are used in the wireless sensor application, as this parameter describes the density of nodes that can be reached by a short secure path in the network. We provide upper and lower bounds for the $k$-hop coverage of a distinct difference configuration with $m$ points, and exploit a connection with $B_{h}$ sequences to construct configurations with maximal $k$-hop coverage. We also construct distinct difference configurations that enable all small vectors to be expressed as the sum of two of the difference vectors of the configuration, an important task for local secure connectivity in the application.
Two-Dimensional Patterns with Distinct Differences -- Constructions, Bounds, and Maximal Anticodes
Simon R. Blackburn,Tuvi Etzion,Keith M. Martin,Maura B. Paterson
Mathematics , 2008,
Abstract: A two-dimensional grid with dots is called a \emph{configuration with distinct differences} if any two lines which connect two dots are distinct either in their length or in their slope. These configurations are known to have many applications such as radar, sonar, physical alignment, and time-position synchronization. Rather than restricting dots to lie in a square or rectangle, as previously studied, we restrict the maximum distance between dots of the configuration; the motivation for this is a new application of such configurations to key distribution in wireless sensor networks. We consider configurations in the hexagonal grid as well as in the traditional square grid, with distances measured both in the Euclidean metric, and in the Manhattan or hexagonal metrics. We note that these configurations are confined inside maximal anticodes in the corresponding grid. We classify maximal anticodes for each diameter in each grid. We present upper bounds on the number of dots in a pattern with distinct differences contained in these maximal anticodes. Our bounds settle (in the negative) a question of Golomb and Taylor on the existence of honeycomb arrays of arbitrarily large size. We present constructions and lower bounds on the number of dots in configurations with distinct differences contained in various two-dimensional shapes (such as anticodes) by considering periodic configurations with distinct differences in the square grid.
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