Influence of a short-term increase in intraluminal pressure, with and without recovery, on ACh-induced dilation in senescent skeletal muscle feed arteries.

Influence of a short-term increase in intraluminal pressure, with and without recovery, on ACh-induced dilation in senescent skeletal muscle feed arteries. John W. Seawright1 and Christopher R. Woodman1,2 1. Vascular Biology Laboratory, Dept. of Health and Kinesiology, Texas A&M University, College Station, TX 77843 2. Dept of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843 We tested the hypothesis that a short-term increase in intraluminal pressure, to mimic a 1 h bout of exercise, would attenuate or reverse age-induced impairments in acetylcholine (ACh)-induced dilation in soleus muscle feed arteries (SFA). In addition, we hypothesized that improved endothelial function would persist following a 2 h recovery period at normal pressure. SFA were isolated from young (4 mo) and old (24 mo) Fischer 344 rats. SFA were cannulated and pressurized at 90 (p90) or 130 (p130) cm H2O for 1 h. At the end of the 1-h treatment period, p130 SFA were lowered to 90 cm H2O and ACh-induced vasodilation was assessed. In a separate group of SFA, pressure was raised to 130 cm H2O for 1 h and subsequently lowered to 90 cm H2O for a 2 h recovery period. ACh-induced vasodilator responses were significantly blunted in old p90 SFA relative to young p90 SFA. Pre-treatment with increased pressure (p130) for 1 h improved ACh-induced dilation in old (not young) SFA. The beneficial effect of pressure in old SFA was not apparent after a 2 h recovery period. To determine the importance of nitric oxide in endothelium-dependent dilation in pressure treated vessels, old SFA were pressurized at 130 cm H2O for 1 h, reset to p90, and ACh-induced vasodilator responses were assessed in the absence or presence of a NOS Inhibitor (L-NNA). Results indicate that the beneficial effect of pressure treatment on ACh-induced dilation was eliminated in the presence of L-NNA. Collectively, these results indicate that a short-term (1 h) increase in intraluminal pressure improves endothelium-dependent dilation in old SFA due to enhanced nitric oxide bioavailability. Contrary to our hypothesis, the beneficial effect of pressure did not persist following a 2 h recovery period. Research supported by AHA grant 0765043Y (CRW), AHA grant 4150031 (CRW), and a Sydney and J.L. Huffines Institute of Sports Medicine Graduate Student Research Grant (JWS). First author classification: Doctoral Studen

Cyclic Adenosine Monophosphate Accumulation and beta-Adrenergic Binding in Unweighted and Denervated Rat Soleus Muscle

Unweighting, but not denervation, of muscle reportedly "spares" insulin receptors, increasing insulin sensitivity. Unweighting also increases beta-adrenergic responses of carbohydrate metabolism. These differential characteristics were studied further by comparing cyclic adenosine monophosphate (cAMP) accumulation and beta-adrenergic binding in normal and 3-day unweighted or denervated soleus muscle. Submaximal amounts of isoproterenol, a p-agonist, increased cAMP accumulation in vitro and in vivo (by intramuscular (IM) injection) to a greater degree (P less than .05) in unweighted muscles. Forskolin or maximal isoproterenol had similar in vitro effects in all muscles, suggesting increased beta-adrenergic sensitivity following unweighting. Increased sensitivity was confirmed by a greater receptor density (B(sub max)) for iodo-125(-)-pindolol in particulate preparations of unweighted (420 x 10(exp -18) mol/mg muscle) than of control or denervated muscles (285 x 10(exp-18) mol/mg muscle). The three dissociation constant (Kd) values were similar (20.3 to 25.8 pmol/L). Total binding capacity (11.4 fmol/muscle) did not change during 3 days of unweighting, but diminished by 30% with denervation. This result illustrates the "sparing" and loss of receptors, respectively, in these two atrophy models. In diabetic animals, IM injection of insulin diminished CAMP accumulation in the presence of theophylline in unweighted muscle (-66% +/- 2%) more than in controls (-42% +'- 6%, P less than .001). These results show that insulin affects CAMP formation in muscle, and support a greater in vivo insulin response following unweighting atrophy. These various data support a role for lysosomal proteolysis in denervation, but not in unweighting, atrophy

SNP-induced Dilation Following a Short-term Intraluminal Pressure Increase in Aged Skeletal Muscle Feed Arteries

A decline in peripheral vascular function occurs with age and is associated with an increased risk for cardiovascular disease. Moderate, aerobic exercise has been documented to improve or reverse the age-related decline in vascular function. The signal(s) associated with exercise responsible for the improvement in vascular function is not known; however, increased intraluminal pressure that occurs during a bout of exercise has been proposed to play an integral role. Previously, we reported that exposure to a short-term increase in intraluminal pressure improves endothelium-dependent vasodilator responses in aged arteries. The purpose of this study was to determine whether pressure treatment enhances endothelium-independent vasodilator responses. We hypothesized that a short-term (1 h) increase in intraluminal pressure, to mimic the intraluminal pressure believed to be present during a 1 h bout of exercise, would not improve endothelium-independent vasodilator responses. Soleus muscle feed arteries from young (4 month) and old (24 month) Fischer 344 rats were isolated, cannulated, and pressurized at 90 (P90) or 130 (P130) cmH20 for 1 h. Following the 1 h pressure treatment, intraluminal pressure was lowered to 90 cmH20 for all vessels and SNP-induced vasodilation was assessed immediately or following a 2 h recovery period. SNP-induced dilation was significantly blunted in old P90 SFA when compared to young P90 SFA. Pre-treatment with increased intraluminal pressure for 1 h improved SNP-induced vasodilator responses and abolished the age group difference between the old and young SFA. Maximal dilation to SNP was greater in the young P130 compared to the young P90 SFA. The effects of the 1 h increased intraluminal pressure treatment were no longer present following a 2 h recovery period. Collectively, these results indicate that treatment of aged arteries with a short-term increase in intraluminal pressure to mimic pressure during a bout of exercise improves endothelium-independent dilation in aged arteries. In addition, these results suggest that a short-term increase in intraluminal pressure, associated with a single bout of exercise, is one signal contributing to the beneficial effect of exercise on vasodilator responses in aged arteries

Aging Impairs ACh-induced Dilation in Skeletal Muscle Feed Arteries: Role of Akt-dependent Phosphorylation of eNOS.

Aging impairs ACh-induced dilation in skeletal muscle feed arteries: role of Akt-dependent phosphorylation of eNOS. Meredith J. Luttrell1, John W. Seawright1, Daniel W. Trott1 and Christopher R. Woodman1,2 1. Dept. of Health and Kinesiology Texas A&M University, College Station, TX 77843 2. Dept of Veterinary Physiology and Pharmacology Texas A&M University, College Station, TX 77843 We tested the hypothesis that impaired nitric oxide (NO)-mediated, endothelium-dependent dilation in aged soleus muscle feed arteries (SFA) is due to an age-related decrement in PI3-kinase(PI3K)/protein kinase B (Akt)-dependent phosphorylation of endothelial NO synthase (eNOS) on serine residue 1177 (p-eNOSser1177). SFA from young (4 mo) and old (24 mo) Fischer 344 rats were cannulated for examination of endothelium-dependent vasodilator responses to acetylcholine (ACh). To determine the mechanism by which aging affected vasodilation to ACh, vasodilator responses were assessed in the absence and presence of Nw-nitro-L-arginine (L-NNA, to inhibit NOS), LY-294002 (to inhibit PI3K), or 1L6-hydroxymethyl-chiro-inositol-2-(R)-2-O-methyl-3-O-octadecyl-sn-glycerocarbonate (AktI, to inhibit Akt). Results indicate that ACh-induced vasodilation was significantly blunted in old SFA, whereas dilation to sodium nitroprusside (a NO donor) was not compromised. The age-group difference in ACh-induced dilation was abolished in the presence of L-NNA, LY-294002, or AktI. In a separate set of experiments, ACh-induced vasodilation was assessed in SFA from young and old rats. SFA were subsequently removed from the pipettes, snap frozen, and immunoblot analysis was used to assess p-AktSer473, p-eNOSser1177, total Akt and total eNOS protein content. ACh-induced vasodilation was blunted in old SFA; however, the p-AktSer473/Akt and p-eNOSser1177/eNOS ratios were similar in young and old SFA. Collectively, these results indicate that NO-mediated dilation is impaired in old SFA; however, the decrement in endothelial function is not due to reduced PI3K/Akt-dependent phosphorylation of eNOS on serine residue 1177

The Effect of Age and Exercise Training on Endothelial Function and Protein:Protein Interactions Among eNOS and Its Regulatory Proteins in Rat Aortas

Previous studies indicate that nitric oxide (NO)-mediated endothelium-dependent dilation declines with age. PURPOSE: The purpose of this study was to test the hypothesis that impaired NO-mediated, endothelium-dependent dilation in aged arteries is due to age-related alterations in protein:protein interactions among endothelial nitric oxide synthase (eNOS) and its regulatory proteins, resulting in reduced NO production in aged arteries. The regulatory proteins of interest in this study are Caveolin-1 (Cav1), an inhibitor of eNOS enzyme activity, and Heat-shock protein 90 (Hsp90), which enhances eNOS activity. METHODS: Young (2 mo) and Old (22 mo) male Fischer 344 rats were endurance exercise trained on a motorized treadmill or remained sedentary for 10wks yielding four groups of rats: 1)Young Sed (4 mo; n = 10), 2)Young Ex (4 mo; n = 10), 3) Old Sed (24 mo; n = 10), and 4) Old Ex (24 mo; n = 10). After the 10 week training period, rats were anesthetized; aortas were removed, cut into rings, and mounted on a wire myograph for assessment of endothelial function. Endothelium-dependent relaxation was assessed in aortic rings using acetylcholine (ACh). Endothelium-independent relaxation was assessed with sodium nitroprusside (SNP). Additional segments of aortas were isolated and snap frozen for use in co-immunoprecipitation experiments to assess Cav1:eNOS and Hsp90:eNOS protein:protein interactions. RESULTS: ACh-induced relaxation was impaired in aged aortic rings. Exercise training improved endothelium-dependent relaxation in old aortic rings such that ACh-induced relaxation in Old Ex aortas did not differ from Young Sed. Results from co-immunoprecipitation experiments revealed no significant age differences in the Cav1:eNOS interactions. Additionally, there was no significant training effect on Cav1:eNOS interaction in either young or old aortas. However, the Hsp90:eNOS interaction revealed a trend toward reduced interaction between the two proteins in the Old Sed group compared to the Young Sed group (p = 0.087). There was no significant training effect on Hsp90:eNOS interaction in young or old aortas. CONCLUSION: Ten weeks of exercise training improves endothelium-dependent relaxation in aortas from old rats. This improvement does not appear to be due to exercise-induced alterations in protein:protein interactions among eNOS and its regulatory proteins

Using fNIRS to Verify Trust in Highly Automated Driving

Trust in automation is crucial for the safe and appropriate adoption of automated driving technology. Current research methods to measure trust mainly rely on subjective scales, with several intrinsic limitations. This empirical experiment proposes a novel method to measure trust objectively, using functional near-infrared spectroscopy (fNIRS). Through manipulating participants’ expectations regarding driving automation credibility, we have induced and successfully measured opposing levels of trust in automation. Most notably, our results evidence two separate yet interrelated cortical mechanisms for trust and distrust. Trust is demonstrably linked to decreased monitoring and working memory, whereas distrust is event-related and strongly tied to affective (or emotional) mechanisms. This paper evidence that trust in automation and situation awareness are strongly interrelated during driving automation usage. Our findings are crucial for developing future driver state monitoring technology that mitigates the impact of inappropriate reliance, or over trust, in automated driving systems

Environmental Hazard Analysis - a Variant of Preliminary Hazard Analysis for Autonomous Mobile Robots

© 2014, Springer Science+Business Media Dordrecht. Robot manufacturers will be required to demonstrate objectively that all reasonably foreseeable hazards have been identified in any robotic product design that is to be marketed commercially. This is problematic for autonomous mobile robots because conventional methods, which have been developed for automatic systems do not assist safety analysts in identifying non-mission interactions with environmental features that are not directly associated with the robot’s design mission, and which may comprise the majority of the required tasks of autonomous robots. In this paper we develop a new variant of preliminary hazard analysis that is explicitly aimed at identifying non-mission interactions by means of new sets of guidewords not normally found in existing variants. We develop the required features of the method and describe its application to several small trials conducted at Bristol Robotics Laboratory in the 2011–2012 period

A global view of the oncogenic landscape in nasopharyngeal carcinoma : an integrated analysis at the genetic and expression levels

Previous studies have reported that the tumour cells of nasopharyngeal carcinoma (NPC) exhibit recurrent chromosome abnormalities. These genetic changes are broadly assumed to lead to changes in gene expression which are important for the pathogenesis of this tumour. However, this assumption has yet to be formally tested at a global level. Therefore a genome wide analysis of chromosome copy number and gene expression was performed in tumour cells micro-dissected from the same NPC biopsies. Cellular tumour suppressor and tumour-promoting genes (TSG, TPG) and Epstein-Barr Virus (EBV)-encoded oncogenes were examined. The EBV-encoded genome maintenance protein EBNA1, along with the putative oncogenes LMP1, LMP2 and BARF1 were expressed in the majority of NPCs that were analysed. Significant downregulation of expression in an average of 76 cellular TSGs per tumour was found, whilst a per-tumour average of 88 significantly upregulated, TPGs occurred. The expression of around 60% of putative TPGs and TSGs was both up-and down-regulated in different types of cancer, suggesting that the simplistic classification of genes as TSGs or TPGs may not be entirely appropriate and that the concept of context-dependent onco-suppressors may be more extensive than previously recognised. No significant enrichment of TPGs within regions of frequent genomic gain was seen but TSGs were significantly enriched within regions of frequent genomic loss. It is suggested that loss of the FHIT gene may be a driver of NPC tumourigenesis. Notwithstanding the association of TSGs with regions of genomic loss, on a gene by gene basis and excepting homozygous deletions and high-level amplification, there is very little correlation between chromosomal copy number aberrations and expression levels of TSGs and TPGs in NPC

Haemoglobin, anaemia, dementia and cognitive decline in the elderly, a systematic review

<p>Abstract</p> <p>Background</p> <p>Anaemia may increase risk of dementia or cognitive decline. There is also evidence that high haemoglobin levels increase risk of stroke, and consequently possible cognitive impairment. The elderly are more at risk of developing dementia and are also more likely to suffer from anaemia, although there is relatively little longitudinal literature addressing this association.</p> <p>Methods</p> <p>To evaluate the evidence for any relationship between incident cognitive decline or dementia in the elderly and anaemia or haemoglobin level, we conducted a systematic review and meta-analyses of peer reviewed publications. Medline, Embase and PsychInfo were searched for English language publications between 1996 and 2006. Criteria for inclusion were longitudinal studies of subjects aged ≥65, with primary outcomes of incident dementia or cognitive decline. Other designs were excluded.</p> <p>Results</p> <p>Three papers were identified and only two were able to be combined into a meta-analysis. The pooled hazard ratio for these two studies was 1.94 (95 percent confidence intervals of 1.32–2.87) showing a significantly increased risk of incident dementia with anaemia. It was not possible to investigate the effect of higher levels of haemoglobin.</p> <p>Conclusion</p> <p>Anaemia is one factor to bear in mind when evaluating risk of incident dementia. However, there are few data available and the studies were methodologically varied so a cautionary note needs to be sounded and our primary recommendation is that further robust research be carried out.</p

Short-term treatment with multi-drug regimens combining BRAF/MEK-targeted therapy and immunotherapy results in durable responses in Braf-mutated melanoma

Targeted and immunotherapy regimens have revolutionized the treatment of advanced melanoma patients. Despite this, only a subset of patients respond durably. Recently, combination strategies of BRAF/MEK inhibitors with immune checkpoint inhibitor monotherapy (α-CTLA-4 or α-PD-1) have increased the rate of durable responses. Based on evidence from our group and others, these therapies appear synergistic, but at the cost of significant toxicity. We know from other treatment paradigms (e.g. hematologic malignancies) that combination strategies with multi-drug regimens (\u3e4 drugs) are associated with more durable disease control. To better understand the mechanism of these improved outcomes, and to identify and prioritize new strategies for testing, we studied several multi-drug regimens combining BRAF/MEK targeted therapy and immunotherapy combinations in a Braf-mutant murine melanoma model (BrafV600E/Pten−/−). Short-term treatment with α-PD-1 and α-CTLA-4 monotherapies were relatively ineffective, while treatment with α-OX40 demonstrated some efficacy [17% of mice with no evidence of disease, (NED), at 60-days]. Outcomes were improved in the combined α-OX40/α-PD-1 group (42% NED). Short-term treatment with quadruplet therapy of immunotherapy doublets in combination with targeted therapy [dabrafenib and trametinib (DT)] was associated with excellent tumor control, with 100% of mice having NED after combined DT/α-CTLA-4/α-PD-1 or DT/α-OX40/α-PD-1. Notably, tumors from mice in these groups demonstrated a high proportion of effector memory T cells, and immunologic memory was maintained with tumor re-challenge. Together, these data provide important evidence regarding the potential utility of multi-drug therapy in treating advanced melanoma and suggest these models can be used to guide and prioritize combinatorial treatment strategies