Sustained Tension Research Articles

Two Koreas, war and health

Despite news in the morning of missile attack threats by North Korea and associated countermeasures by South Korea, like most South Koreans I spend a peaceful weekend playing with my kids at a playground. I hear from my father, who recently moved from the southernmost island to Seoul, that he was treated for lunch by his elderly neighbours seeking information about the island in case of evacuation. Although living on the Korean peninsula has been implied to be very dangerous in the international media, the South Korean people have been rather calm, as they have already spent their lifetime under such sustained tensions and war threats. While assuming that verbal provocations by North Korea may not have any significant health impacts, as an epidemiology and public health researcher I reflect on how the Korean War (1950–53) and subsequent political situation have affected the health of the two Koreas, what lessons there would be for international research communities from comparison studies of the two Koreas, and what should be the appropriate response of public health professionals to a potential war.

Biomechanics of superior oblique Z-tenotomy: Is it different from unguarded tenotomy?

IntroductionA recent report suggests that 70-80% Z-tenotomy of the superior oblique (SO) effectively treats A-pattern strabismus associated with overdepression in adduction. We examined the effect of Z-tenotomy on SO tendon biomechanics.MethodsFresh bovine SO tendons were reduced to the 16mm long x 8mm wide dimensions similar to the human SO tendon, and clamped in a custom micro-tensile load cell under physiological conditions of temperature and humidity. Minimal pre-load was applied to avoid slackness. Tendons were elongated by 20% of original length following Z-tenotomies, made with scissors from opposite sides of the tendon, spaced 6.4 mm apart and each encompassing 0, 40, 60, or 80% tendon width. Transient and sustained tensions were monitored using a precision strain gauge with digital sampling. Control experiments were performed in similar-sized specimens of bovine rectus tendon, and isotropic latex.ResultsZ-tenotomy of latex caused a linear reduction in force transmission reaching zero at ∼95% tenotomy. In contrast, Z-tenotomy of SO and rectus tendons caused progressive reduction in force transmission reaching a negligible value at only 80% tenotomy.DiscussionUnlike isotropic latex, the parallel fiber structure of tendons reduces shear force transfer across tendon width and enhances the biomechanical effect of Z-tenotomy. Z-tenotomy <80% progressively reduces force transmission in the tendon, but Z-tenotomy of ≥80% reduces force transmission to zero just as complete tenotomy. The marked SO tendon elongation observed surgically at the end point of 80% Z-tenotomy represents loss of all SO force transmission.Conclusions80% or greater SO Z-tenotomy is biomechanically equivalent to complete unguarded tenotomy. IntroductionA recent report suggests that 70-80% Z-tenotomy of the superior oblique (SO) effectively treats A-pattern strabismus associated with overdepression in adduction. We examined the effect of Z-tenotomy on SO tendon biomechanics. A recent report suggests that 70-80% Z-tenotomy of the superior oblique (SO) effectively treats A-pattern strabismus associated with overdepression in adduction. We examined the effect of Z-tenotomy on SO tendon biomechanics. MethodsFresh bovine SO tendons were reduced to the 16mm long x 8mm wide dimensions similar to the human SO tendon, and clamped in a custom micro-tensile load cell under physiological conditions of temperature and humidity. Minimal pre-load was applied to avoid slackness. Tendons were elongated by 20% of original length following Z-tenotomies, made with scissors from opposite sides of the tendon, spaced 6.4 mm apart and each encompassing 0, 40, 60, or 80% tendon width. Transient and sustained tensions were monitored using a precision strain gauge with digital sampling. Control experiments were performed in similar-sized specimens of bovine rectus tendon, and isotropic latex. Fresh bovine SO tendons were reduced to the 16mm long x 8mm wide dimensions similar to the human SO tendon, and clamped in a custom micro-tensile load cell under physiological conditions of temperature and humidity. Minimal pre-load was applied to avoid slackness. Tendons were elongated by 20% of original length following Z-tenotomies, made with scissors from opposite sides of the tendon, spaced 6.4 mm apart and each encompassing 0, 40, 60, or 80% tendon width. Transient and sustained tensions were monitored using a precision strain gauge with digital sampling. Control experiments were performed in similar-sized specimens of bovine rectus tendon, and isotropic latex. ResultsZ-tenotomy of latex caused a linear reduction in force transmission reaching zero at ∼95% tenotomy. In contrast, Z-tenotomy of SO and rectus tendons caused progressive reduction in force transmission reaching a negligible value at only 80% tenotomy. Z-tenotomy of latex caused a linear reduction in force transmission reaching zero at ∼95% tenotomy. In contrast, Z-tenotomy of SO and rectus tendons caused progressive reduction in force transmission reaching a negligible value at only 80% tenotomy. DiscussionUnlike isotropic latex, the parallel fiber structure of tendons reduces shear force transfer across tendon width and enhances the biomechanical effect of Z-tenotomy. Z-tenotomy <80% progressively reduces force transmission in the tendon, but Z-tenotomy of ≥80% reduces force transmission to zero just as complete tenotomy. The marked SO tendon elongation observed surgically at the end point of 80% Z-tenotomy represents loss of all SO force transmission. Unlike isotropic latex, the parallel fiber structure of tendons reduces shear force transfer across tendon width and enhances the biomechanical effect of Z-tenotomy. Z-tenotomy <80% progressively reduces force transmission in the tendon, but Z-tenotomy of ≥80% reduces force transmission to zero just as complete tenotomy. The marked SO tendon elongation observed surgically at the end point of 80% Z-tenotomy represents loss of all SO force transmission. Conclusions80% or greater SO Z-tenotomy is biomechanically equivalent to complete unguarded tenotomy. 80% or greater SO Z-tenotomy is biomechanically equivalent to complete unguarded tenotomy.

Breathe (review)

Reviewed by: Breathe Claire Gross Crossan, Sarah . Breathe. Greenwillow, 2012. 373p. Trade ed. ISBN 978-0-06-211869-1 $17.99 E-book ed. ISBN 978-0-06-211871-4 $9.99 R Gr. 9-12. In an environmentally devastated future marked by severely depleted oxygen levels, the remaining humans, their numbers vastly reduced, live in pod cities. There the population is divided into rigid, brutal social strata: Premiums are the privileged few who can afford the extra oxygen needed for things like exercise and sex, while auxiliaries live in constant breathlessness. And then there's the Resistance, who know that the powerful company Breathe doesn't just manufacture oxygen, it manufactures its scarcity as well. Quinn, a goodhearted Premium, and Bea, his auxiliary best friend who believes she can reach Premium status with enough hard work, are leaving the dome for a camping trip (air tanks and all) when Alina, a Resistance member on the run after she steals tree cuttings, uses them to get through security. Out in the desolate world, Quinn and Bea are drawn into the Resistance as they try to help Alina reach its headquarters. The narration rotates among the three teens, each of whom experiences a distinct and compelling character arc. Bea, defined by her compassion, finds strength in rage as she realizes that the system she's worked so hard to ascend is a lie. Quinn, who's led an easy life and knows it, struggles with his own weakness ("I want to promise to die for the cause, but who knows what I'd do at the end if I were starving and desperate?"), while Alina relearns the idea of friendship and becomes disenchanted with the Resistance's means. With short chapters, tight pacing, and expertly sustained tension that makes the most of the trio of narrative viewpoints, this joins the ranks of Roth's Divergent (BCCB 5/11) and Wells' Partials (BCCB 5/11) as a provocative, character-driven, and action-packed dystopian series opener to watch out for. Copyright © 2012 The Board of Trustees of the University of Illinois

Simulated Bladder Pressure Stimulates Human Bladder Smooth Muscle Cell Proliferation via the PI3K/SGK1 Signaling Pathway

A mechanical stimulus on detrusor tissue is critical to bladder outlet obstruction progression and functional bladder tissue engineering. A hypothesis is that mechanical stimulus triggers human bladder smooth muscle cell proliferation. To help better understand this relationship of bladder function to growth at the cellular level we used a novel method of applying cyclic hydrodynamic pressure that simulates the bladder cycle to cell cultures. We detected the proliferation response of human bladder smooth muscle cells (4310, ScienCell™) to different pressures as well as the signal transduction mechanism of this process. Human bladder smooth muscle cells cultured in scaffolds underwent 4 pressures (0, 100, 200 and 300 cm H(2)O) for 24 hours, as controlled by a BioDynamic® bioreactor. We then used flow cytometry to examine cell cycle distribution, and polymerase chain reaction and immunoblot to quantify SGK1 and AKT expression and activation in each group. SGK1 was silenced in human bladder smooth muscle cells using small interfering RNA to validate the role of SGK1 in mediating pressure induced cell proliferation. Compared with the 0 cm H(2)O control group, human bladder smooth muscle cells in the 200 and 300 cm H(2)O groups showed increased cell proliferation. SGK1 expression and activity were also increased while AKT, another downstream signal of PI3K, did not change significantly. SGK1 silencing abolished the increases in cell proliferation induced by pressure. To our knowledge we provide the first report of cyclic hydrodynamic pressure stimulating the proliferation of human bladder smooth muscle cells cultured in scaffolds. The signal transduction mechanism for this process is involved with the PI3K/SGK1 and not the PI3K/AKT signaling pathway.

Cooling-induced contraction in ileal longitudinal smooth muscle of guinea-pig.

The ileal longitudinal smooth muscle developed a transient contraction on cooling from 37 degrees C to 1 degree C in normal Ca2+ (2.5 mM) medium. The transient contraction was not inhibited by pretreatment with the Ca2+ antagonist, D-600 (1 X 10(-6)M). The contractions were sustained by cooling to 1 degree C in the presence of added Ca2+ greater than 10 mM. After the pretreatment with D-600, when the muscle incubated in normal medium with added 20 mM Ca2+ had been cooled to 1 degree C, a phasic response was only seen. However, D-600 did not inhibit the sustained contraction at 1 degree C after incubation in the presence of added 20 mM Ca2+. It is suggested that the transient and sustained contraction at 1 degree C is maintained by Ca2+ release from a cellular site, probably the cell membrane and it requires more calcium for the sustained tension.

Different views of history: Shades of irredentism along the Laos–Cambodia border

The administrative boundary between Laos and Cambodia is amongst the least studied international borders in Southeast Asia. Since Laos and Cambodia became independent in 1953–54, relatively minor but sustained tensions have characterised border relations. An important reason for disagreements is irredentist feelings. Some ethnic Lao in both Laos and Cambodia believe that part of northeastern Cambodia should be added to Laos, while some ethnic Khmer in Cambodia insist that their border should be extended to include part of southern Laos. Different emphases and framings of history have contributed to irredentism and the development of identities in relation to the border.

A simple protocol for assessing inter-trial and inter-examiner reliability for two noninvasive measures of limb muscle strength

Noninvasive measures of limb muscle strength are quite useful in preclinical translational studies that use mouse models of muscle disease, peripheral nerve disease, and movement disorders. The present study uses a simple protocol for assessing both inter-trial and inter-examiner reliability for two noninvasive methods of assessing limb strength in dystrophic (mdx) and wild type mice. One method, termed the whole body tension (WBT) method or escape test, measures the total phasic pulling tension exerted by the fore- and hindlimbs while a mouse attempts to escape into a darkened tube. Another procedure, termed the four limb wire grid holding test, measures the minimal amount of sustained tension (physical impulse) exerted by the fore- and hindlimbs while the mouse hangs suspended in an upside-down position. A comparison of the two methods revealed significant inter-trial and inter-examiner correlations in each procedure, although the WBT procedure consistently produced higher correlations than the four limb wire grid holding test. Inter-trial reliability for each test was higher than inter-examiner reliability, indicating that each longitudinal series of tests is best performed by a single investigator. The holding test also did not consistently detect differences between wild type and mdx populations at ages greater than 4 months. These results demonstrate the utility of a simple protocol for assessing the reliability of noninvasive tests that measure limb strength, and should be useful in comparing different functional measures in a broad range of translational studies.

Dollar Dominance, Euro Aspirations: Recipe for Discord?

AbstractAfter nearly a century of dominance of the international monetary system, has the US dollar finally met its match in the euro? When Europe's economic and monetary union (EMU) came into existence in 1999, many observers predicted that the euro would soon join America's greenback at the peak of global finance. Achievements, however, have fallen short of aspiration. After an initial spurt of enthusiasm, international use of the euro actually appears now to be levelling off, even stalling, and so far seems confined largely to a limited range of market sectors and regions. The euro has successfully attained a place second only to the greenback – but it remains, and is likely to remain, a quite distant second without a determined effort by EMU authorities to promote their money's global role. The temptation will surely be great. In practical terms, it is difficult to imagine that EMU authorities will refrain entirely from trying to promote a greater role for the euro. But that, in turn, could turn out to be a recipe for discord with the United States, which has never made any secret of its commitment to preserving the greenback's worldwide dominance. A struggle for monetary leadership could become a source of sustained tensions in US–European relations. Fortunately, however, there seems relatively little risk of a destabilizing escalation into outright geopolitical conflict.

Effect of Sustained Tension on Bladder Smooth Muscle Cells in Three-Dimensional Culture

Previous studies demonstrated that bladder cells respond to changes in their mechanical environments by exhibiting alterations in cellular functions, such as hypertrophy or fibrosis. In the present study, we hypothesize that changes in smooth muscle cell (SMC) behavior triggered by mechanical stimuli may represent a phenotypic shift between contractile and synthetic phenotypes. Using a custom-made device, rat bladder SMCs were cultured in three-dimensional (3-D) collagen gels and exposed to sustained tension. When compared to no-tension controls, SMCs exposed to tension exhibited significantly (p < 0.05) higher expression of alpha-smooth muscle actin (alpha-SMA), while cell population density was similar in both groups. In addition, both mean and median aspect ratios of SMCs in 3-D collagen constructs exposed to tension were significantly (p < 0.05) greater than those of cells cultured under no externally applied tension, indicating that there are more elongated, spindle-shaped cells in the tension group. These SMCs in 3-D cultures exposed to tension also exhibited cellular alignment along the direction of applied tension. Since contractile SMCs are known to exhibit greater expression of phenotypic marker proteins as well as a more elongated morphology, we concluded that sustained tension on cells is an important mechanical stimulus for maintenance of the contractile phenotype of bladder SMCs in vitro.

“Ambassadors of Commerce“: The Commercial Traveler in British Culture, 1800–1939

This paper presents a reading of British literary representations of commercial travelers between 1800 and 1939. Three forms of representation are used: nonfiction representations by others, travelers' self-representations, and fictional representations. We find remarkable continuity in representations of commercial travelers across this long time period, particularly in terms of a sustained tension between the image of the disreputable “drummer” and the more respectable “model” salesman. These readings and findings are used to address two debates: one concerned with the timing of any transition to “modern” selling and salesmanship in Britain; and the second having to do with the processes whereby British society accommodated itself to modernity, commercialization, and the birth of a consumer society.

Social change in America: from the Revolution through the Civil War

The processes of social change in the late colonial period and early years of the new Republic made a dramatic imprint on the character of American society. These changes over a century or more were rooted in the origins of the United States, its rapid expansion of people and territory, its patterns of economic change and development, and the conflicts that led to its cataclysmic division and reunification through the Civil War. Christopher Clark's brilliant account of these changes in the social relationships of Americans breaks new ground in its emphasis on the connections between the crucial importance of free and unfree labor, regional characteristics, and the sustained tension between arguments for geographic expansion versus economic development. Mr. Clark traces the significance of families and households throughout the period, showing how work and different kinds of labor produced a varied access to power and wealth among free and unfree, male and female, and how the character of social elites was confronted by democratic pressures. He shows how the features of the different regions exercised long-term influences in American society and politics and were modified by pressures for change. And he explains how the widening gap between the claims of free labor and those of slavery fueled the continuing dispute over the best economic course for the nation's future and led ultimately to the Civil War. Like other long-running divisions in American society, however, this dispute was not fully resolved by the war's outcome. Social Change in America is a compelling new overview of the social dynamics of America's early years.

Cardiac sympathetic nerve activity and ventricular fibrillation during acute myocardial infarction in ambulent sheep

The association between cardiac sympathetic nerve activity (CSNA) and ventricular fibrillation (VF) following acute myocardial infarction (MI) has not been assessed in a conscious animal model. For 60 minutes post-MI, blood pressure (BP), heart rate (HR) and CSNA were recorded continuously. Resistant sheep (group A, n=10) were compared to susceptible sheep (group B, n-10) who developed fatal VF or sustained ventricular tachycardia VT. MI was induced under pethidine/diazepam analgesia by applying sustained tension to a coronary suture.

Myosin Phosphatase Regulatory Pathways

In many ways, the smooth muscle cell (SMC) has been at the forefront in defining cellular signaling pathways. For example, the initial description of agonist-dependent intracellular calcium ([Ca2+]i) transients was made on vertebrate vascular SMC using aqueorin as the indicator.1 Delineation of nitric oxide (NO) and cGMP signaling was first accomplished in smooth muscle.2,3 And more recently, insights into the general mechanisms of gene transcription that dictate phenotypic traits of cells are being defined by smooth muscle specific gene expression.4,5 It should come as no surprise then that the interactions among many signaling pathways in cells should be explained first in the SMC. Perhaps the reason for the central position of the SMC in defining paradigms in cellular biology is that there are well-defined physiologic end points amenable to measurement (ie, contractile force) and even better described and easily quantified biochemical pathways that underlie said physiologic end points (ie, myosin regulatory light chain phosphorylation). From a historical perspective, the role of protein phosphorylation in smooth muscle contraction as a paradigm for cell signaling follows only that for the control of glycogen metabolism (see 6,7 for reviews). Increases in the levels of cytosolic [Ca2+]i initiate smooth muscle contraction by binding to the universal intracellular Ca2+ receptor protein, calmodulin (CaM), which in turn binds to and activates smooth muscle myosin light chain kinase (MLCK). Activated MLCK catalyzes the phosphorylation serine-19 of the regulatory myosin light chain (MLC) thereby increasing cross-bridge cycling and the rate of tension development. Dephosphorylation of MLC is catalyzed by smooth muscle specific myosin light chain phosphatase (MLCP). Decreases in cytosolic [Ca2+]i and MLC dephosphorylation are considered salient events in smooth muscle relaxation. What has become apparent only within the last decade is the fact that …

Ruling women: queenship and gender in Anglo-Saxon literature

In Ruling Women, Stacy S. Klein explores how queens functioned as imaginative figures in Anglo-Saxon texts. Focusing on pre-Conquest works ranging from Bede to Aelfric, Klein argues that Anglo-Saxon writers drew upon accounts of legendary royal wives to construct cultural ideals of queenship during a time when that institution was undergoing profound change. Also a study of gender, her book examines how Anglo-Saxon writers used women of the highest social rank to forge broader cultural ideals of femininity, even as they used female voices to articulate far less comfortable social truths. Capitalizing on queens' strong associations with intercession, Anglo-Saxon writers consistently looked to royal women as mediatory figures for negotiating sustained tensions. Yet as authors appropriated legendary queens and inserted them into contemporary Anglo-Saxon culture, these royal peaceweavers simultaneously threatened to destroy existing unities and to expose the fragility of seemingly entrenched social formations. Ruling Women offers us a way to understand Anglo-Saxon texts as both literary monuments and historical documents, and thus to illuminate the ideological fissures and cultural stakes of Anglo-Saxon literary practice.

Demystifying the role of culture in innovative regional economies

James A. (2005) Demystifying the role of culture in innovative regional economies, Regional Studies 39 , 1197–1216. Within the regional learning and innovation literature, the precise impact of regional ‘culture’ on firms' competitive performance remains unspecified. In response, this paper draws on research on Utah's high-tech industrial agglomeration, embedded in a highly visible regional culture: Mormonism. Focusing specifically on computer software firms, the paper first shows how the cultural embeddedness of firms in the region is best understood as a series of sustained tensions between: (1) self-identified regional cultural traits imported into the firm; versus (2) key elements of corporate cultures known to underpin innovation. Second, the paper measures the material impact of that regional cultural embedding on firms' innovative capacities and hence abilities to compete. Finally, it outlines the wider relevance of the author's work with regard to the spatial limits imposed on high-tech cluster policy by cultural context.

WILLIAM III'S MILITARY AND POLITICAL CAREER IN NEO-ROMAN CONTEXT, 1672–1702

William III's military and political career was marked by a sustained tension between his obsessive struggle against France and the fear caused by his accession to enhanced titles of power. Crucial to William's shift from stadholderate to kingship was his assumption of emergency powers in 1672 to defend his country against French invasion. Throughout his stadholderate (1672–1702), he came to be seen by his Dutch republican opponents as a Roman dictator intent on using military power to break the harmony of the constitution, while Orangist propaganda tried to present the rule of the One as the best remedy to the recurrent danger of civil war and anarchy. Spurred by the Ryswick treaty of September 1697 and fuelled by a deeply engrained tradition of resistance to any expanded military establishment, the standing army debates of 1697–9 came as an effort to understand a major political controversy in the light of the history of republican Rome. The political theorists of the New Country Party strove to reassert the superiority of civil over military power by showing how the decay of the Roman Republic had been caused by a departure from the civic militia paradigm and a drift towards military monarchy which fostered the growth of tyranny. It was thought that England's commitment to a prolonged war effort would entail a similar process and imperil the age-old balance between king and parliament. The contention of this article is that the standing army debates of 1697–9 can be construed as an encounter between Dutch and English neo-Romanism, crystallizing in the controversial figure of William. An overall view of William's military and political career and the search for elements of continuity in his supporters' and his opponents' arguments will serve to look at the role of historicism in the construction of a late seventeenth-century Anglo-Dutch ideological space.

IN VIVO TENSION SUSTAINED BY FASCIAL SLING IN PUBOVAGINAL SLING SURGERY FOR FEMALE STRESS URINARY INCONTINENCE

In pubovaginal sling surgery arguments have focused on selecting stronger sling materials, better suturing methods and superior fixation techniques. However, the grounding information prerequisite for these arguments is still lacking, ie the in vivo tension sustained by the sling. We designed this study to obtain this information. A total of 10 female patients (mean age 65.4 years) underwent pubovaginal sling surgery while under epidural anesthesia. A strip of rectus fascia (2 x 6 cm) was isolated. Each end of the fascia was anchored with a 1-zero Prolene suture (Ethicon, Somerville, New Jersey). The fascial sling was placed over the proximal urethra. Both ends of the prolene (polypropylene) sutures were transferred to the lower abdominal incision and tied on each other. The fascial sling was adjusted just to touch the proximal urethra without elevating it. We hooked the tied polypropylene suture on a digital force gauge to measure the tension sustained by the fascial sling. Patients were instructed to cough, and the tension was measured at different bladder volumes (100, 200, 300, 400 ml) and in 2 positions (horizontal and operative table tilted head-up 20 degrees). Intravesical pressure was monitored with a pressure transducer to ensure adequate cough strength. We also investigated the in vitro length-tension relationship and tensile strength of 3 rectus fascia strips (0.5 x 6 cm) obtained from 3 of these patients. Mean tension +/- SEM sustained by the fascial sling during cough in the horizontal position was 0.046 +/- 0.004, 0.043 +/- 0.006, 0.0475 +/- 0.006 and 0.0485 +/- 0.007 kg at 100, 200, 300 and 400 ml bladder volume, respectively. Bladder volume did not statistically affect the sustained tension. The 20-degree head-up position also did not statistically change the tension sustained. In vitro study showed that the fascia strip could be stretched for a mean of 0.4 cm before sling tension began to increase. A mean load of 2.4 kg broke 0.5 x 6 cm strips. In the horizontal and mild tilting positions during an increase in intra-abdominal pressure, the fascial sling only sustains minor tension, which is far less than the maximal load needed to break fascial strips. The excellent elasticity of the fascia may dissipate the straining force and partly explains the measured small sustained tension.

Capsazepine, a vanilloid antagonist, abolishes tonic responses induced by 20-HETE on guinea pig airway smooth muscle

The aim of this study was to delineate the mode of action of 20-hydroxy-eicosatetraenoic acid (20-HETE) in airway smooth muscle (ASM) cells. ASM metabolizes arachidonic acid by various enzymatic pathways, including the cytochrome P-450 (CYP-450) omega-hydroxylase, which leads to the production of 20-HETE, a bronchoconstrictive eicosanoid. The present study demonstrated that 20-HETE induced concentration-dependent tonic responses in ASM, whereas transient responses were recorded in Ca2+-free solution, suggesting an intracellular Ca2+ release process. 20-HETE inotropic responses were abolished by 36 microM 2-aminoethoxydiphenyl borate or 1 microM thapsigargin but were insensitive to 10 microM ryanodine, indicating that inositol triphosphate receptors likely control the release of intracellular Ca2+. Sustained tension, which required Ca2+ entry, was partially blocked by 1 microM nifedipine (an L-type) and 100 microM Gd3+ (a nonselective cationic channel blocker). Moreover, in the absence of selective 20-HETE receptor antagonists, 20-HETE tonic responses were inhibited in a concentration-dependent manner (0.1-10 microM) by capsazepine, a well-characterized vanilloid receptor antagonist. Capsazepine was also observed to reverse cumulative responses to 20-HETE and capsaicin, a TRPV1 agonist. In addition, capsazepine pretreatment largely modified the sustained inotropic responses to 20-HETE, suggesting that 20-HETE cross-reacted with TRPV1 receptors with a low affinity (microM) or that its specific receptor was inhibited by the vanilloid antagonist. Data obtained using RHC-80267, ONO-RS-082, and eicosatetraynoic acid, respective inhibitors of diacylglycerol-lipase, phospholipase A2, and CYP-450 omega-hydroxylase, reveal that intracellular arachidonic acid production and its 20-HETE metabolite may be responsible for the activation of nonselective cationic channels and tonic responses.

IN/VISIBLE GEOGRAPHIES: ABSENCE, EMERGENCE, PRESENCE, AND THE FINE ART OF IDENTITY CONSTRUCTION

ABSTRACTIn this paper I draw on interviews with professional visual artists in Toronto, Canada to reconstruct an occupation‐specific reading of the urban landscape. I use a detailed examination of one specific occupational identity to reveal the intricate relationship between self, work, and context at different spatial scales. The underlying mechanism that supports the articulation and negotiation of artistic identities, I argue, is the sustained tension between absence and presence, visibility and invisibility within different spaces of the urban fabric.

Regulation of the Cystic Fibrosis Transmembrane Conductance Regulator Channel by β-Adrenergic Agonists and Vasoactive Intestinal Peptide in Rat Smooth Muscle Cells and Its Role in Vasorelaxation

Regulation of the Cystic Fibrosis Transmembrane Conductance Regulator Channel by β-Adrenergic Agonists and Vasoactive Intestinal Peptide in Rat Smooth Muscle Cells and Its Role in Vasorelaxation