Effect of L-arginine infusion on glucose disposal during exercise in humans

Purpose: We have previously shown that local infusion of a nitric oxide synthase (NOS) inhibitor attenuates increases in leg glucose uptake during exercise in humans. We have also shown that infusion of the NOS substrate, L-arginine (L-Arg), increases glucose clearance, although the mechanisms involved were not determined. A potential mechanism for NO-mediated glucose disposal is via interactions with NOS and the energy sensor AMPactivated protein kinase (AMPK). The aim of this study was to determine the mechanism(s) by which L-Arg infusion increases glucose disposal during exercise in humans by examining total NOS activity and AMPK signaling.

Methods: Seven males cycled for 120 min at 64% T 1% V˙ O2peak, during which the [6,6-2H]glucose tracer was infused. During the final 60 min of exercise, either saline alone (Control, CON), or saline containing L-Arg HCl (L-Arg, 30 g at 0.5 gIminj1) was coinfused in a double-blind, randomized, counterbalanced order.

Results: L-Arg increased the glucose rate of disappearance and glucose clearance rate during exercise; however, this was accompanied by a 150% increase in plasma insulin concentration from 65 to 75 min (P G 0.05) that remained significantly elevated until 90 min of exercise. Skeletal muscle AMPK signaling, nNOSK phosphorylation by AMPK, and total NOS activity increased to a similar extent in the two trials.

Conclusions: The increase in glucose disposal after L-Arg infusion during exercise is likely due to the significantly higher plasma insulin concentration.

Performing the technical image

The recent public multi-screen performance of formalist experimental animation by film artists such as Guy Sherwin, Bruce McLure and Greg Pope respond to the immediacy and speed of new digital technologies, the rise of Vilem Flusser’s ‘technical image’ and the consequent disappearance of reflective space identified by Prensky, Kroker, Virilio and Postman. Flusser’s ‘technical images’, benefiting from the digital’s painterly hyper-malleability structure and content, signifier and signified, so much the subject of Peter Gidal’s arguments in support of his concept of ‘materialist film’ in the 1970’s.  In the digital those formal editing strategies used to create the ‘technical image’ within analogue image construction that traditionally took place in the artist’s studio within the camers and optical printer are now executed inside the computer, having migrated into the post-production process.  Within the work of these artist’s recent multi-screen presentations these manipulations are now-elusively experienced in live ephemeral performance, re-forming and laying bare those processes that have been rendered invisible in digital technology.  The significance of this work partly lies in its ability to communicate historical information a-historically. Guy Sherwin and Lynn Loo’s method in their play with 16mm film flashes and after-images and Sherwin’s mirror performance further reproduces Goethe’s method from his Theory of Colours (1840). Greg Pope’s scratch performances re-enact the operation of Konrad Zuse’s 1930’s computing machine. Affinities are drawn between Bruce McLure’s immersive overpowering sonic and flicker performances with Edwin Land’s 1960’s experiments on colour constancy on which Land’s Retinex Theory of colour is based.

Effect of increased blood glucose availability on glucose kinetics during exercise

This study examined the effect of increased blood glucose availability on glucose kinetics during exercise. Five trained men cycled for 40 min at 77 ± 1% peak oxygen uptake on two occasions. During the second trial (Glu), glucose was infused at a rate equal to the average hepatic glucose production (HGP) measured during exercise in the control trial (Con). Glucose kinetics were measured by a primed continuous infusion ofd-[3-3H]glucose. Plasma glucose increased during exercise in both trials and was significantly higher in Glu. HGP was similar at rest (Con, 11.4 ± 1.2; Glu, 10.6 ± 0.6 μmol ⋅ kg−1 ⋅ min−1). After 40 min of exercise, HGP reached a peak of 40.2 ± 5.5 μmol ⋅ kg−1 ⋅ min−1in Con; however, in Glu, there was complete inhibition of the increase in HGP during exercise that never rose above the preexercise level. The rate of glucose disappearance was greater (P < 0.05) during the last 15 min of exercise in Glu. These results indicate that an increase in glucose availability inhibits the rise in HGP during exercise, suggesting that metabolic feedback signals can override feed-forward activation of HGP during strenuous exercise.

Effect of heat stress on glucose kinetics during exercise

To identify the mechanism underlying the exaggerated hyperglycemia during exercise in the heat, six trained men were studied during 40 min of cycling exercise at a workload requiring 65% peak pulmonary oxygen uptake (V˙o 2 peak) on two occasions at least 1 wk apart. On one occasion, the ambient temperature was 20°C [control (Con)], whereas on the other, it was 40°C [high temperature (HT)]. Rates of glucose appearance and disappearance were measured by using a primed continuous infusion of [6,6-2H]glucose. No differences in oxygen uptake during exercise were observed between trials. After 40 min of exercise, heart rate, rectal temperature, respiratory exchange ratio, and plasma lactate were all higher in HT compared with Con (P < 0.05). Plasma glucose levels were similar at rest (Con, 4.54 ± 0.19 mmol/l; HT, 4.81 ± 0.19 mmol/l) but increased to a greater extent during exercise in HT (6.96 ± 0.16) compared with Con (5.45 ± 0.18;P < 0.05). This was the result of a higher glucose rate of appearance in HT during the last 30 min of exercise. In contrast, the glucose rate of disappearance and metabolic clearance rate were not different at any time point during exercise. Plasma catecholamines were higher after 10 and 40 min of exercise in HT compared with Con (P < 0.05), whereas plasma glucagon, cortisol, and growth hormone were higher in HT after 40 min. These results indicate that the hyperglycemia observed during exercise in the heat is caused by an increase in liver glucose output without any change in whole body glucose utilization.

A novel sensing technique for monitoring pitting corrosion of stainless steel type 316L

A novel electrochemically integrated multi-electrode array namely the wire beam electrode(WBE) in combination with noise signatures analysis has been designed to monitor pittingcorrosion of one of the best corrosion resistance ferrous alloys, stainless steel type 316L.From the direct correlation of electrochemical potential noise signatures and galvanic currentdistribution maps during pitting corrosion processes, two characteristic noise patterns wereobserved prior to stable pit formation: (i) the characteristic ‘peak’ of rapid potential transient,towards less negative direction, followed by recovery (termed noise signature I) was found tocorrelate with the disappearance of unstable anode; (ii) the characteristic noise pattern ofquick potential changes towards less negative direction followed by no recovery (termed noisesignature II) was found to correspond with the massive disappearance of minor anodes leadingto formation of highly localized major anodes in the galvanic current distribution maps.

Animals as disregarded pawns in family violence : exclusionary practices of feminist based refuge policies

Commonly agreed upon is the relationship between family violenceand violence toward nonhuman animals. Workers in the field of family violence also acknowledge that women may delay leaving a violent home due to loyalty to their nonhuman counterparts, and because refuge policies often do not allow them to accompany humans into safe shelter. The recent work of Clifton Flynn has indicated the relationship between nonhuman animals and human animals to be one of responsive interaction, with theoretical analyses most often based upon Goffman’s theory of symbolic interaction. Despite literature indicating the level of harm inflicted upon nonhuman family members in violent homes, and requests from women and children that they accompany them to safe shelter, refuge policies often negate the possibility of this occurring. This article critiques the feminist ideals on which refuge policies are based, and in doing so, argues that justice is denied to nonhuman animals. Their existence in the violent home is maintained by lack of choices available to their human counterpart, and is enforced by feminist ideals, which are ironically based upon equity. Unless feminist principles are challenged, nonhuman family members will continue to be denied justice in violent families where escape is the only option to ensure safety.

Loss of insulin-mediated microvascular perfusion in skeletal muscle is associated with the development of insulin resistance

Aim: The aetiology of the development of type 2 diabetes remains unresolved. In the present study, we assessed whether an impairment of insulin-mediated microvascular perfusion occurs early in the onset of insulin resistance. Materials and methods: Hooded Wistar rats were fed either a normal diet (ND) or a high-fat diet (HFD) for 4 weeks. Anaesthetized animals were subjected to an isoglycaemic hyperinsulinaemic clamp (3 or 10 mU/min/kg × 2 h), and measurements were made of glucose infusion rate (GIR), hindleg glucose uptake, muscle glucose uptake by 2-deoxy-d-glucose (R′g), glucose appearance (Ra), glucose disappearance (Rd), femoral blood flow (FBF) and hindleg 1-methylxanthine disappearance (1-MXD, an index of microvascular perfusion). Results: Compared with ND-fed animal, HFD feeding led to a mild increase in fasting plasma glucose and plasma insulin, without an increase in total body weight. During the clamps, HFD rats showed an impairment of insulin-mediated action on GIR, hindleg glucose uptake, R′g, Ra, Rd and FBF, with a greater loss of insulin responsiveness at 3 mU/min/kg than at 10 mU/min/kg. The HFD also impaired insulin-mediated microvascular perfusion as assessed by 1-MXD. Interestingly, 1-MXD was the only measurement that remained unresponsive to the higher dose of 10 mU/min/kg insulin. Conclusions: We conclude that the early stage of insulin resistance is characterized by an impairment of the insulin-mediated microvascular responses in skeletal muscle. This is likely to cause greater whole body insulin resistance by limiting the delivery of hormones and nutrients to muscle.

Performing an intervention

What does it mean to intervene, or to perform an intervention? Presumptively conflictual, the term finds meaning in its clinical and behavioural application as an enforced practice of modification: one performs an intervention on an (often) unwilling subject. Cut one way, you could tell a history of sex/ualities education as a history of interventions of this kind: efforts to interrupt and redirect affective investments, sexual practices and undesirable identifications. The sexually active young person, the homosexual, the single mother, people of colour, people with disabilities, indigenous people, promiscuous poor people – these are some of intervention’s favourite things. These are subjects constituted in part through histories of psycho-therapeutic, medical and health educational correction, histories that are still elaborating themselves through a series of familiar contemporary concerns and campaigns.

Reducing intoxication among bar patrons: some lessons from prevention of drinking and driving

Intoxication in and around licensed premises continues to be common, despite widespread training in the responsible service of alcohol and laws prohibiting service to intoxicated individuals. However, research suggests that training and the existence of laws are unlikely to have an impact on intoxication without enforcement, and evidence from a number of countries indicates that laws prohibiting service to intoxicated individuals are rarely enforced. Enforcement is currently hampered by the lack of a standardized validated measure for defining intoxication clearly, a systematic approach to enforcement and the political will to address intoxication. We argue that adoption of key principles from successful interventions to prevent driving while intoxicated could be used to develop a model of consistent and sustainable enforcement. These principles include: applying validated and widely accepted criteria for defining when a person is ‘intoxicated’; adopting a structure of enforceable consequences for violations; implementing procedures of unbiased enforcement; using publicity to ensure that there is a perceived high risk of being caught and punished; and developing the political will to support ongoing enforcement. Research can play a critical role in this process by: developing and validating criteria for defining intoxication based on observable behaviour; documenting the harms arising from intoxication, including risk curves associated with different levels of intoxication; estimating the policing, medical and social costs from intoxicated bar patrons; and conducting studies of the cost-effectiveness of different interventions to reduce intoxication.

Political Islam and human security

In the wake of the September 11 and subsequent terrorist attacks, the academic and media commentaries on Islam the religion and Islam the basis for political ideology haves received an unprecedented high level of exposure and attention. The acts of political violence by extremist groups and the omnipresent war on terror have added fresh uncertainties to an already complex global order. Just as terrorism and counter-terrorism are locked in a mutually re-enforcing symbiosis, the sense of insecurity felt by Muslims and non-Muslims alike is mutually dependent and has the potential to escalate. This general assessment holds true for Muslims living in the Muslim world and beyond. The pervasive sense of being under attack physically and culturally by the United States and its allies has contributed to a growing unease among Muslims and re-enforced deep-seated mistrust of the ‘West’. Public articulation of such misgivings has in turn, lent credence to Western observers who posit an inherent antipathy between the West and the Muslim world. The subsequent policies that have emerged in this context of fear and mutual distrust have contributed to the vicious cycle of insecurity.

Leave entitlements, time off work and the household financial impacts of quarantine compliance during an H1N1 outbreak

Background The Australian state of Victoria, with 5.2 million residents, enforced home quarantine during a H1N1 pandemic in 2009. The strategy was targeted at school children. The objective of this study was to investigate the extent to which parents’ access to paid sick leave or paid carer’s leave was associated with (a) time taken off work to care for quarantined children, (b) household finances, and (c) compliance with quarantine recommendations. Methods We conducted an online and telephone survey of households recruited through 33 schools (85% of eligible schools), received 314 responses (27%), and analysed the subsample of 133 households in which all resident parents were employed. Results In 52% of households, parents took time off work to care for quarantined children. Households in which no resident parent had access to leave appeared to be less likely to take time off work (42% vs 58%, p=0.08) although this difference had only borderline significance. Among parents who did take time off work, those in households without access to leave were more likely to lose pay (73% vs 21%, p<0.001). Of the 26 households in which a parent lost pay due to taking time off work, 42% experienced further financial consequences such as being unable to pay a bill. Access to leave did not predict compliance with quarantine recommendations. Conclusions Future pandemic plans should consider the economic costs borne by households and options for compensating quarantined families for income losses.

Does reduced mobility through fragmented landscapes explain patch extinction patterns for three honeyeaters?

1.Habitat loss and associated fragmentation are major drivers of biodiversity decline, and understanding how they affect population processes (e.g. dispersal) is an important conservation goal. In a large-scale test employing 10 × 10 km units of replication, three species of Australian birds, the fuscous honeyeater, yellow-tufted honeyeater and white-plumed honeyeater, responded differently to fragmentation. The fuscous and yellow-tufted honeyeaters are ‘decliners’ that disappeared from suitable habitat in landscapes where levels of tree-cover fell below critical thresholds of 17 and 8%, respectively. The white-plumed honeyeater is a ‘tolerant’ species whose likelihood of occurrence in suitable habitat was independent of landscape-level tree-cover. 2.To determine whether the absence of the two decliner species in low tree-cover landscapes can be explained by reduced genetic connectivity, we looked for signatures of reduced mobility and gene flow in response to fragmentation across agricultural landscapes in the Box-Ironbark region of north-central Victoria, Australia. 3.We compared patterns of genetic diversity and population structure at the regional scale and across twelve 100 km2 landscapes with different tree-cover extents. We used genetic data to test landscape models predicting reduced dispersal through the agricultural matrix. We tested for evidence of sex-biased dispersal and sex-specific responses to fragmentation. 4.Reduced connectivity may have contributed to the disappearance of the yellow-tufted honey-eater from low tree-cover landscapes, as evidenced by male bias and increased relatedness among males in low tree-cover landscapes and signals of reduced gene flow and mobility through the agricultural matrix. We found no evidence for negative effects of fragmentation on gene flow in the other decliner, the fuscous honeyeater, suggesting that undetected pressures act on this species. As expected, there was no evidence for decreased movement through fragmented landscapes for the tolerant white-plumed honeyeater. 5.We demonstrated effects of habitat loss and fragmentation (stronger patterns of genetic differentiation, increased relatedness among males) on the yellow-tufted honeyeater above the threshold at which probability of occurrence dropped. Increasing extent and structural connectivity of habitat should be an appropriate management action for this species and other relatively sedentary woodland specialist species for which it can be taken as representative.

The poetic presentation of philosophy:Leo Strauss on Plato’s “symposium”

This essay undertakes a close analysis of Leo Strauss’s remarkable but undertreated Leo Strauss on Plato’s “Symposium,” reading it as opening a privileged purview of his own (and his students’) wider understandings of philosophy, poetry, and politics. The essay begins by drawing out Strauss’s three framing justifications for his manner of reading the Symposium as a document in the “ancient quarrel” of philosophy and poetry concerning which of the two should rightly shape the culture and ethical ideals of the Greeks (part 1). Then, following the course of Plato’s Symposium, the essay ascends through Strauss’s readings of the first five speeches in Plato’s dialogue (part 2) toward the highlight of Strauss’s reading, namely, his three remarkable sessions on Socrates’s speech. Part 3 analyses Strauss’s reading of this speech up to its climax, which Strauss argues involves the philosophical “demotion of poetry”: a criticism of poets as motivated by the Eros of fame and of tragic poetry as at its best creating captivating images of gods and heroes which reflect their creators’ self-love and patriotic love of “one’s own,”as against any transpolitical truth. Part 4 then looks at Strauss’s unusual reading of the culmination of Socrates’s great speech (Diotima on the “higher mysteries”) alongside Alkibiades’s speech in the Symposium as representing Plato’s “poetic presentation of philosophy.” The essay becomes more critical as it proceeds. Strauss’s reading of the Symposium, like his reading of the Republic, is remarkable for its own “demotion of metaphysics” in Plato, and in my concluding remarks, I will question this status, or disappearance, of metaphysics in Strauss’s Platonism and whether this disappearance compromises Strauss' ability to differentiate philosophy as he sees it from poetry.

Late Permian marine ecosystem collapse began in deeper waters: Evidence from brachiopod diversity and body size changes

Analysis of Permian-Triassic brachiopod diversity and body size changes from different water depths spanning the continental shelf to basinal facies in South China provides insights into the process of environmental deterioration. Comparison of the temporal changes of brachiopod diversity between deepwater and shallow-water facies demonstrates that deepwater brachiopods disappeared earlier than shallow-water brachiopods. This indicates that high environmental stress commenced first in deepwater settings and later extended to shallow waters. This environmental stress is attributed to major volcanic eruptions, which first led to formation of a stratified ocean and a chemocline in the outer shelf and deeper water environments, causing the disappearance of deep marine benthos including brachiopods. The chemocline then rapidly migrated upward and extended to shallow waters, causing widespread mass extinction of shallow marine benthos. We predict that the spatial and temporal patterns of earlier onset of disappearance/extinction and ecological crisis in deeper water ecosystems will be recorded during other episodes of rapid global warming.

Effect of cell-surface components and metabolites of lactic acid bacteria and probiotic organisms on cytokine production and induction of CD25 expression in human peripheral mononuclear cells

In the current study, the relative contribution of cell-surface components (CSC) and cell-free supernatants (CFS) in the immuno-modulatory properties of 17 strains of probiotic and lactic acid bacteria (LAB) was assessed. The production of pro- and antiinflammatory cytokines including IL-2, IL-4, IL-10, IL-12 p70, IFN-γ, tumor necrosis factor-α (TNF-α), and transforming growth factor-β was measured at different time points after stimulation of buffy coat derived-peripheral blood mononuclear cells (PBMC) from healthy donors with CSC and CFS of probiotic and LAB. Results showed that CSC of probiotic and LAB strains induced production of T helper 1 and 2 type cytokines. Transforming growth factor-β was stimulated at highest concentrations, followed by IL-10 and TNF-α. The CFS of all tested bacterial strains induced PBMC for significantly high levels of IL-10 secretion compared with unstimulated cells, but the values were less than lipopolysaccharide-stimulated cells. Cytokines due to CFS stimulation showed declined concentration for IL-2, TNF-α, and IL-4, and complete disappearance of IL-12, IFN-γ, and transforming growth factor-β in the cultured medium at 96 h of incubation. Results of cytokine data demonstrate proinflammatory TNF-α immune responses are mainly directed through cell-surface structures of probiotic and LAB, but antiinflammatory immune responses are mediated both by metabolites and cell-surfaces of these bacteria. The induction of CD4(+)CD25(+) regulatory T cells after stimulation of PBMC with CSC and CFS of probiotic and LAB showed regulatory T cell activity appeared to be influenced both by the CSC and metabolites, but was principally triggered by cell surfaces of probiotic and LAB strains.