Effect of streptozotocin-induced diabetes on glycogen resynthesis in fasted rats post-high-intensity exercise

It has recently been shown that food intake is not essential for the resynthesis of the stores of muscle glycogen in fasted animals recovering from high-intensity exercise. Because the effect of diabetes on this process has never been examined before, we undertook to explore this issue. To this end, groups of rats were treated with streptozotocin (60 mg/kg body mass ip) to induce mild diabetes. After 11 days, each animal was fasted for 24 h before swimming with a lead weight equivalent to 9% body mass attached to the tail. After exercise, the rate and the extent of glycogen repletion in muscles were not affected by diabetes, irrespective of muscle fiber composition. Consistent with these findings, the effect of exercise on the phosphorylation state of glycogen synthase in muscles was only minimally affected by diabetes. In contrast to its effects on nondiabetic animals, exercise in fasted diabetic rats was accompanied by a marked fall in hepatic glycogen levels, which, surprisingly, increased to preexercise levels during recovery despite the absence of food intake.

Molecular aspects of boundary lubrication by human lubricin : effect of disulfide bonds and enzymatic digestion

Lubricin (LUB) is a glycoprotein of the synovial cavity of human articular joints, where it serves as an antiadhesive, boundary lubricant, and regulating factor for the cartilage surface. It has been proposed that these properties are related to the presence of a long, extended, heavily glycosylated and highly hydrated mucinous domain in the central part of the LUB molecule. In this work, we show that LUB has a contour length of 220 ± 30 nm and a persistence length of ≤10 nm. LUB molecules aggregate in oligomers where the protein extremities are linked by disulfide bonds. We have studied the effect of proteolytic digestion by chymotrypsin and removal of the disulfide bonds, both of which mainly affect the N− and C− terminals of the protein, on the adsorption, normal forces, friction (lubrication) forces, and wear of LUB layers adsorbed on smooth, negatively charged mica surfaces, where the protein naturally forms lubricating polymer brush-like layers. After in situ digestion, the surface coverage was drastically reduced, the normal forces were altered, and both the coefficient of friction and the wear were dramatically increased (the COF increased to μ = 1.1−1.9), indicating that the mucinous domain was removed from the surface. Removal of disulfide bonds did not change the surface coverage or the overall features of the normal forces; however, we find an increase in the friction coefficient from μ = 0.02−0.04 to μ = 0.13−1.17 in the pressure regime below 6 atm, which we attribute to a higher affinity of the protein terminals for the surface. The necessary condition for LUB to be a good lubricant is that the protein be adsorbed to the surface via its terminals, leaving the central mucin domain free to form a low-friction, surface-protecting layer. Our results suggest that this “end-anchoring” has to be strong enough to impart the layer a sufficient resistance to shear, but without excessively restricting the conformational freedom of the adsorbed proteins.

Effect of sodium selenite-enriched reperfusion solutions on rat cardiac ischemia reperfusion injury

Cardiac surgery often generates oxidative stress leading to ischemia reperfusion injury (I-R). Antioxidants have been shown to prevent this injury and have been added to cardioplegic solutions to assist in recovery. In this study, we tested the effectiveness of sodium selenite in protecting against ischemia reperfusion injury and investigated the mechanisms behind this protection. Hearts from male Wistar rats were subjected to ischemia reperfusion using the Langendorf model. Krebs-Henseleit perfusion solutions were supplemented with 0,0.1, 0.5, 1.0, and 10μM sodium selenite. Hearts were perfused for 30 min and then subjected to 22.5 min of global ischemia followed by 45 min reperfusion. Heart rate, ischemic contracture, end diastolic pressure, and developed ventricular pressure were monitored. At the completion of the experiment, hearts were homogenized and tissue extracts were assayed for glutathione peroxidase (GSH-Px) and thioredoxin reductase (Thx-Red) activity. Sodium selenite, at a concentration of 0.5 μM, demonstrated a protective effect on the recovery of cardiac function following I-R, as evidenced by a lower end diastolic pressure and enhanced recovery of rate pressure product. There was no beneficial effect observed in hearts perfused with 0.1 μM sodium selenite-supplemented buffer, whereas poorer functional recovery was observed in hearts perfused with 10 μM sodium selenite-supplemented buffer. The beneficial effect of sodium selenite was not mediated through increased activity of GSH-Px or Thx-Red. This study demonstrates that the addition of sodium selenite to reperfusion solutions, at an optimal concentration of 0.5 μM, assists in cardiac recovery following ischemia reperfusion.

Effect of nozzle polarity and connection on electrospinning of polyacrylonitrile nanofibers

In this study, two power supplies having positive/ground and negative/ground electrode output ends were used separately for electrospinning of polyacrylonitrile nanofibers. Depending on type of power supply and electrode connection, electrospinning led to different fiber diameters and deposition areas. The nozzle was connected to a high voltage end while the collector was grounded. Regardless of power supply used, finer fibers with a larger deposition area were obtained, compared to that using the same setup but with a reverse electrode connection. With an increase in the applied voltage, fiber deposition area, and productivity increased for all electrode connections. Grounded nozzles provide much better control over fiber deposition than the reverse electrode connections. Finite element modeling was used to analyze the electric field profile in the electrospinning zone. It was revealed that high electric intensity was mainly located in the part that was charged with a high voltage electrode, which could explain the differences in fiber diameter and deposition area.

Effect of vascular endothelial growth factor upregulation on retinal gene expression in the Kimba mouse

Background:  The Kimba mouse carries a human vascular endothelial growth factor transgene causing retinal neovascularisation similar to that seen in diabetic retinopathy. Here, we examine the relationship between differential gene expression induced by vascular endothelial growth factor overexpression and the architectural changes that occur in the retinae of these mice.

Methods:  Retinal gene expression changes in juvenile and adult Kimba mice were assayed by microarray and compared with age-matched wild-type littermates. Transcription of selected genes was validated by quantitative real-time polymerase chain reaction. Protein translation was determined using immunohistochemistry and enzyme-linked immunosorbent assay.

Results:  Semaphorin 3C was upregulated, and nuclear receptor subfamily 2, group 3, member 3 (Nr2e3) was downregulated in juvenile Kimba mice. Betacellulin and endothelin 2 were upregulated in adults. Semaphorin 3C colocalized with glial fibrillary acidic protein in Müller cells of Kimba retinae at greater signal intensities than in wild type. Endothelin 2 colocalised to Müller cell end feet and extended into the outer limiting membrane. Endothelin receptor type B staining was most pronounced in the inner nuclear layer, the region containing Müller cell somata.

Conclusions:  An early spike in vascular endothelial growth factor induced significant long-term retinal neovascularisation associated with changes to the retinal ganglion, photoreceptor and Müller cells. Overexpression of vascular endothelial growth factor led to dysregulation of photoreceptor metabolism through differential expression of Nr2e3, endothelin 2, betacellulin and semaphorin 3C. Alterations in the expression of these genes may therefore play key roles in the pathological mechanisms that result from retinal neovascularisation.

Internet cognitive behavioural therapy for panic disorder : does the inclusion of stress management information improve end-state functioning?

Previous research has established Internet-based cognitive behavioural therapy (CBT) for panic disorder (PD) as effective in reducing panic severity and frequency. There is evidence, however, that such programs are less effective at improving overall end-state functioning, defined by a PD clinician severity rating of ≤2 and panic free. In order to test the effect on end-state functioning of the incorporation of stress management material within a CBT program for PD, 32 people with PD were randomised to either Internet-based CBT (PO1), Internet-based CBT plus stress management (PO2) or an Internet-based information-only control condition (IC). Both CBT treatments were more effective at posttreatment assessment than the control condition in reducing PD severity, panic and agoraphobia-related cognition, negative affect and self-ratings of health. PO2 was more effective than PO1 at posttreatment assessment on PD severity and general anxiety, although at 3-month follow-up these differences were no longer apparent. This study provides further support for the efficacy of Internet-based CBT for PD and suggests that although the incorporation of stress management material confers short-term advantages over a standard program, it is not associated with any longer term improvements on panic severity and related cognitions, negative affect, general wellbeing and end-state functioning.

Estimating the intensity of ward admission and its effect on emergency department access block

Emergency department access block is an urgent problem faced by many public hospitals today. When access block occurs, patients in need of acute care cannot access inpatient wards within an optimal time frame. A widely held belief is that access block is the end product of a long causal chain, which involves poor discharge planning, insufficient bed capacity, and inadequate admission intensity to the wards. This paper studies the last link of the causal chain-the effect of admission intensity on access block, using data from a metropolitan hospital in Australia. We applied several modern statistical methods to analyze the data. First, we modeled the admission events as a nonhomogeneous Poisson process and estimated time-varying admission intensity with penalized regression splines. Next, we established a functional linear model to investigate the effect of the time-varying admission intensity on emergency department access block. Finally, we used functional principal component analysis to explore the variation in the daily time-varying admission intensities. The analyses suggest that improving admission practice during off-peak hours may have most impact on reducing the number of ED access blocks.

The volume of water filtered by a Continuous Plankton Recorder sample: the effect of ship speed

The Continuous Plankton Recorder (CPR) survey is one of the largest plankton-monitoring programmes in the world. Since 1931, the CPR has collected ∼380 000 samples, each representing 10 miles of tow. It has been assumed that the volume of seawater filtered by each sample remained constant and close to 3 m3. In this study, the volume filtered for each CPR sample was measured on two routes (SA and IN), monitored by the CPR survey, between 1995 and 2000. Although the filtered volume was near the theoretical value of 3 m3 on the SA route (3.2 m3), it was significantly higher on the IN route (3.8 m3). A significant negative relationship was found between the volume filtered and the speed of the ships. This relationship indicates that the faster the speed of the ship, the lower the volume filtered. This could have implications for the CPR survey as the speed of the ships has increased continuously since the end of the 1950s. However, no significant correlation was found between the long-term changes in the speed of the ships and two commonly used indicators of plankton variability: the Phytoplankton Colour and the Total Copepods indices. This absence of relationship may indicate that the effect found is small in comparison with the influence of hydroclimatic forcing, although a more extensive study is needed to confirm these findings.

Effect of weighted vest suit worn during daily activities on running speed, jumping power, and agility in young men

Effect of weighted vest suit worn during daily activities on running speed, jumping power, and agility in young men. J Strength Cond Res 26(11): 3030-3035, 2012-Previous weighted vest interventions using exercise in addition to hypergravity have been successful in improving postural balance and power production capacity. The purpose of this study was to investigate if hypergravity alone in daily activities excluding sporting activities is effective in improving neuromuscular performance in young adults. Eight male subjects (age = 32 [SD: 6] years, height = 178 [5] cm, and body mass = 81 [8] kg) wore weighted vests 3 d.wk-1 for 3 weeks during waking hours, excluding sporting activities. Control group comprised 9 male subjects (age = 32 [6] years, height = 179 [5] cm, and body mass = 83 [9] kg). Performance was assessed with countermovement jump (body mass normalized peak power), figure-of-8 running test (running time), and running velocity test at baseline and at the end of the intervention. At baseline, the groups did not differ from each other (multivariate analysis of variance [MANOVA] p = 0.828). A significant group × time interaction (MANOVA F = 5.1, p = 0.015) was observed for performance variables. Analysis of covariance indicated that the intervention improved the figureof- 8 running time (p = 0.016) (22.2 vs. 0.5%), whereas normalized peak power (0.0 vs. 1.6%) and running velocity (1.3 vs. 0.1%) were unaffected (p ≥ 0.095). Wearing weighted vests was effective in slightly improving agility-related performance in young men. Because the effect was small, applying hypergravity only during exercise probably suffices. It appears that a proper volume and intensity of hypergravity could be in the order of 5-10% body weight vest worn during up to 50% of the training sessions for a period of 3-4 weeks.

On the strength of dislocation interactions and their effect on latent hardening in pure Magnesium

This study is dedicated to the quantification of latent hardening and its effect on the plasticity of pure hexagonal magnesium. To this end, discrete dislocation dynamics simulations are used to (1) extract latent hardening parameters coupling different slip systems, and to (2) assess the validity of two existing constitutive models linking slip system strength to dislocation densities on all slip systems. As hexagonal materials deform via activation of different slip modes, each with different mobilities and lattice friction stress, the effects of the latter on latent hardening evolution are also investigated. It is found that the multi-slip formulation proposed by Franciosi and Zaoui gives accurate predictions when multiple interactions are involved while the formulation suggested by Lavrentev and Pokhil systematically overestimates the flow stress. Similar to FCC materials, it is also found that collinear interactions potentially contribute the most to latent hardening. Basal/pyramidal c + a interactions are found to be very strong, while interactions involving second-order pyramidal c + a primary dislocations appear to be the weakest ones. Finally, the latent hardening parameters, extracted from the discrete dislocation dynamics simulations, are used in polycrystal simulations and the impact of finely accounting for latent hardening on predictions of the macroscopic anisotropic response is shown to be of significant importance.

Extraordinary television time travel and the wonderful end to the working day

In this article I will present two arguments. First, the argument that the time travel television series historically provided viewers with a spectacular temporal and spatial alternative to the routine of everyday life, the regulation of television scheduling, and the small-world confines of domestic subjectivity. Taking the decades of the 1970s and 1980s, predominantly in a UK viewing environment, I will suggest that the special effect rendering of the time travel sequence expanded the viewer’s material universe, and affectively wrenched the television set free from the strictures of scheduling and realist programming. Further, the time travel series readily and regularly took the domestic space, the ordinary day and the everyman/ person into awesome environments and situations that suggested alternative lifestyles and behaviours, with a different existential tempo and rhythm. At a narrative, thematic, meta- textual, and aesthetically spectacular level, television time travel saw to the wonderful end of the working day. Case studies include Sapphire and Steal, Dr Who, and Quantum Leap. Second, the article will argue that rather than the contemporary time travel television series being an extraordinary alternative to ordinary life, they instead articulate convergence culture, deregulation, multiple channel viewing, and time-shift culture where there is no such thing as an ordinary working day or domestic viewing context.

The Christmas effect-special dividend announcements

This paper examines the Halloween effect in special dividend announcements. We find that firms are more likely to announce special dividends at the end of a year, especially in the months of November and December. There is a Halloween effect in the announcements, but more importantly, there is a Christmas effect in the propensity and abnormal returns of special dividends. This paper provides initial evidence on the Christmas effect of special dividend payments. It links monthly effects in stock returns and corporate events to explain the likelihood of the occurrence of special dividend announcements. The results of this paper shed light on why corporate events are more likely to occur in some periods, but less likely to occur in others.

Costs and advance directives at the end of life: a case of the ‘Coaching Older Adults and Carers to have their preferences Heard (COACH)’ trial

BACKGROUND: Total costs associated with care for older people nearing the end of life and the cost variations related with end of life care decisions are not well documented in the literature. Healthcare utilisation and associated health care costs for a group of older Australians who entered Transition Care following an acute hospital admission were calculated. Costs were differentiated according to a number of health care decisions and outcomes including advance directives (ADs).

METHODS: Study participants were drawn from the Coaching Older Adults and Carers to have their preferences Heard (COACH) trial funded by the Australian National Health and Medical Research Council. Data collected included total health care costs, the type of (and when) ADs were completed and the place of death. Two-step endogenous treatment-regression models were employed to test the relationship between costs and a number of variables including completion of ADs.

RESULTS: The trial recruited 230 older adults with mean age 84 years. At the end of the trial, 53 had died and 80 had completed ADs. Total healthcare costs were higher for younger participants and those who had died. No statistically significant association was found between costs and completion of ADs.

CONCLUSION: For our frail study population, the completion of ADs did not have an effect on health care utilisation and costs. Further research is needed to substantiate these findings in larger and more diverse clinical cohorts of older people.

The effect of holiday haemodialysis treatments on patient mood, adverse symptoms and subjective wellbeing using the Big Red Kidney Bus

BACKGROUND AND AIMS: People with end-stage kidney disease receiving haemodialysis are restricted to holidays where dialysis services are readily available. Holiday dialysis in regional, rural and remote areas is particularly challenging. The aims of this study were to (1) evaluate the wellbeing of those who received dialysis in a holiday haemodialysis bus, and (2) to measure patient wellbeing with that of a comparable cohort of haemodialysis patients. METHODS: A three machine haemodialysis bus, the Big Red Kidney Bus, was built to enable people, their families and carers to take holidays across a range of tourist destinations in Victoria, Australia. Measures included pre-post subjective wellbeing, dialysis symptoms and mood questionnaires complemented by post semi-structured telephone interviews. RESULTS: Participating holidaymakers were positive about the haemodialysis bus service and the standard of care experienced. They reported decreased dialysis side effects of fatigue, muscle cramp, and dry skin. The overall number of reported symptoms decreased and the perceived level of bother associated with symptoms also decreased. No changes in subjective wellbeing and mood were detected. Mean Personal Wellbeing Index scores were significantly higher than in a comparative haemodialysis sample. CONCLUSION: The Big Red Kidney Bus provided a safe and feasible holiday dialysis service. Holidaymakers' wellbeing was reflected by the decreased dialysis patient side effects.