The effect of short-term canola oil ingestion on oxidative stress in the vasculature of stroke-prone spontaneously hypertensive rats

Background: This study aimed to determine if 25 days of canola oil intake in the absence of excess dietary salt or together with salt loading affects antioxidant and oxidative stress markers in the circulation. A further aim was to determine the mRNA expression of NADPH oxidase subunits and superoxide dismutase (SOD) isoforms in the aorta of stroke-prone spontaneously hypertensive (SHRSP) rats.

Methods: Male SHRSP rats, were fed a defatted control diet containing 10% wt/wt soybean oil or a defatted treatment diet containing 10% wt/wt canola oil, and given tap water or water containing 1% NaCl. Blood was collected at the end of study for analysis of red blood cell (RBC) antioxidant enzymes, RBC and plasma malondialdehyde (MDA), plasma 8-isoprostane and plasma lipids. The aorta was removed and the mRNA expression of NOX2, p22phox, CuZn-SOD, Mn-SOD and EC-SOD were determined.

Results: In the absence of salt, canola oil reduced RBC SOD and glutathione peroxidase, and increased total cholesterol and LDL cholesterol compared with soybean oil. RBC glutathione peroxidase activity was significantly lower in both the salt loaded groups compared to the soybean oil only group. In addition, RBC MDA and plasma HDL cholesterol were significantly higher in both the salt loaded groups compared to the no salt groups. Plasma MDA concentration was higher and LDL cholesterol concentration lower in the canola oil group loaded with salt compared to the canola oil group without salt. The mRNA expression of NADPH oxidase subunits and SOD isoforms were significantly reduced in the canola oil group with salt compared to canola oil group without salt.

Conclusion: In conclusion, these results indicate that canola oil reduces antioxidant status and increases plasma lipids, which are risk factors for cardiovascular disease. However, canola oil in combination with salt intake increased MDA, a marker of lipid peroxidation and decreased NAPDH oxidase subunits and aortic SOD gene expression.

Arginase II inhibition prevents nitrate tolerance

BACKGROUND AND PURPOSE Nitrate tolerance, the loss of vascular responsiveness with continued use of nitrates, remains incompletely understood and is a limitation of these therapeutic agents. Vascular superoxide, generated by uncoupled endothelial NOS (eNOS), may play a role. As arginase competes with eNOS for L-arginine and may exacerbate the production of reactive oxygen species (ROS), we hypothesized that arginase inhibition might reduce nitrate tolerance.

EXPERIMENTAL APPROACH Vasodilator responses were measured in aorta from C57Bl/6 and arginase II knockout (argII –/–) mice using myography. Uncoupling of eNOS, determined as eNOS monomer : dimer ratio, was assessed using low-temperature SDS-PAGE and ROS levels were measured using L-012 and lucigenin-enhanced chemiluminescence.

KEY RESULTS Repeated application of glyceryl trinitrate (GTN) on aorta isolated from C57Bl/6 mice produced a 32-fold rightward shift of the concentration–response curve. However this rightward shift (or resultant tolerance) was not observed in the presence of the arginase inhibitor (s)-(2-boronethyl)-L-cysteine HCl (BEC; 100 µM) nor in aorta isolated from argII –/– mice. Similar findings were obtained after inducing nitrate tolerance in vivo. Repeated administration of GTN in human umbilical vein endothelial cells induced uncoupling of eNOS from its dimeric state and increased ROS levels, which were reduced with arginase inhibition and exogenous L-arginine. Aortae from GTN tolerant C57Bl/6 mice exhibited increased arginase activity and ROS production, whereas vessels from argII –/– mice did not.

CONCLUSION AND IMPLICATIONS Arginase II removal prevents nitrate tolerance. This may be due to decreased uncoupling of eNOS and consequent ROS production.

Glutathione peroxidase-1 reduces influenza A virus-induced lung inflammation

Oxidative stress caused by excessive reactive oxygen species production is implicated in influenza A virus–induced lung disease. Glutathione peroxidase (GPx)-1 is an antioxidant enzyme that may protect lungs from  such damage. The objective of this study was to determine if GPx-1 protects the lung against influenza A virus–induced lung inflammation in vivo.

Correlation between a self-administered walk test and a standardised Six Minute Walk Test in adults

This study was undertaken to assess the correlation between a self-administered, adapted Six Minute Walk Test (the Home-Heart-Walk) and the standard Six Minute Walk Test based on the American Thoracic Society guideline. A correlational study was conducted at a university campus in Sydney, Australia. Thirteen healthy volunteers underwent the Home-Heart-Walk and the standard Six Minute Walk Test on a single occasion. The distance that participants walked during the two tests was assessed using Pearson's correlation. The correlation between the Home-Heart-Walk and the Six Minute Walk Test distance was 0.81. The Home-Heart-Walk distance was highly correlated to the standard Six Minute Walk Test distance in this study. This relationship provides confidence for further research in populations to facilitate monitoring and evaluation.

Validation and development of a clinical prediction rule in clinically suspected community-acquired pneumonia

To develop a mathematical model to predict the probability of having community-acquired pneumonia and to evaluate an already developed prediction rule that has not been validated in a clinical scenario.

Childhood wheeze phenotypes show less than expected growth in FEV1 across adolescence

Better characterization of childhood wheeze phenotypes using newer statistical methods provides a basis for addressing the heterogeneity of childhood asthma. Outcomes of these phenotypes beyond childhood are unknown.

Nervous control of circulation--the role of gasotransmitters, NO, CO, and H2S.

The origins and actions of gaseous signaling molecules, nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H(2)S) in the mammalian cardiovascular system have received considerable attention and it is evident that these three "gasotransmitters" perform a variety of homeostatic functions. The origins, actions and disposition of these gasotransmitters in the piscine vasculature are far from resolved. In most fish examined to date, NO or NO donors are generally in vitro and in vivo vasodilators acting via soluble guanylyl cyclase, although there is evidence for NO-mediated vasoconstriction. Injection of sodium nitroprusside into trout causes hypotension that is attributed to a reduction in systemic resistance. Unlike mammals, NO does not appear to have an endothelial origin in fish blood vessels as an endothelial NO synthase has not identified. However, neural NO synthase is prevalent in perivascular nerves and is the most likely source of NO for cardiovascular control in fish. CO is a vasodilator in lamprey and trout vessels, and it, like NO, appears to exert its action, at least in part, via guanylyl cyclase and potassium channel activation. Inhibition of CO production increases resting tone in trout vessels suggestive of tonic CO activity, but little else is known about the origin or control of CO in the fish vasculature. H(2)S is synthesized by fish vessels and its constrictory, dilatory, or even multi-phasic actions, are both species- and vessel-specific. A small component of H(2)S-mediated basal activity may be endothelial in origin, but to a large extent H(2)S affects vascular smooth muscle directly and the mechanisms are unclear. H(2)S injected into the dorsal aorta of unanesthetized trout often produces oscillations in arterial blood pressure suggestive of H(2)S activity in the central nervous system as well as peripheral vasculature. Collectively, these studies hint at significant involvement of the gasotransmitters in piscine cardiovascular function and hopefully provide a variety of avenues for future research.

Aortic intima-media thickness measured by trans-abdominal ultrasound as an early life marker of subclinical atherosclerosis

Atherosclerosis is a chronic inflammatory process that begins in early life. Improved identification of markers of early atherosclerosis via neonatal aortic intima-media thickness (aIMT) measurement may allow the development of interventions to prevent or reduce later cardiovascular disease.

Neuronal classification and distribution in the central nervous system of the female mud crab, Scylla olivacea

The mud crab, Scylla olivacea, is one of the most economically valuable marine species in Southeast Asian countries. However, commercial cultivation is disadvantaged by reduced reproductive capacity in captivity. Therefore, an understanding of the general and detailed anatomy of central nervous system (CNS) is required before investigating the distribution and functions of neurotransmitters, neurohormones, and other biomolecules, involved with reproduction. We found that the anatomical structure of the brain is similar to other crabs. However, the ventral nerve cord (VNC) is unlike other caridian and dendrobrachiate decapods, as the subesophageal (SEG), thoracic and abdominal ganglia are fused, due to the reduction of abdominal segments and the tail. Neurons in clusters within the CNS varied in sizes, and we found that there were five distinct size classes (i.e., very small globuli, small, medium, large, and giant). Clusters in the brain and SEG contained mainly very small globuli and small-sized neurons, whereas, the VNC contained small-, medium-, large-, and giant-sized neurons. We postulate that the different sized neurons are involved in different functions. Microsc. Res. Tech. 77:189–200, 2014. © 2013 Wiley Periodicals, Inc.

Evaluation of neck muscle size: long-term reliability and comparison of methods

Although it is important for prospective studies, the reliability of quantitative measures of cervical muscle size on magnetic resonance imaging is not well established. The aim of the current work was to assess the long-term reliability of measurements of cervical muscle size. In addition, we examined the utility of selecting specific sub-regions of muscles at each vertebral level, averaging between sides of the body, and pooling muscles into larger groups. Axial scans from the base of skull to the third thoracic vertebra were performed in 20 healthy male subjects at baseline and 1.5 years later. We evaluated the semi-spinalis capitis, splenius capitis, spinalis cervicis, longus capitis, longus colli, levator scapulae, sternocleidomastoid, anterior scalenes and middle with posterior scalenes. Bland-Altman analysis showed all measurements to be repeatable between testing-days. Reliability was typically best when entire muscle volume was measured (co-efficients of variation (CVs): 3.3-8.1% depending on muscle). However, when the size of the muscle was assessed at specific vertebral levels, similar measurement precision was achieved (CVs: 2.7-7.6%). A median of 4-6 images were measured at the specific vertebral levels versus 18-37 images for entire muscle volume. This would represent considerable time saving. Based on the findings we also recommend measuring both sides of the body and calculating an average value. Pooling specific muscles into the deep neck flexors (CV: 3.5%) and neck extensors (CV: 2.7%) can serve to reduce variability further. The results of the current study help to establish outcome measures for interventional studies and for sample size estimation.

Influence of prolonged bed-rest on spectral and temporal electromyographic motor control characteristics of the superficial lumbo-pelvic musculature

Little is known about the motor control of the lumbo-pelvic musculature in microgravity and its simulation (bed-rest). Analysis of spectral and temporal electromyographic variables can provide information on motor control relevant for normal function. This study examined the effect of 56-days of bed-rest with 1-year follow-up in 10 male subjects on the median frequency and the activation timing in surface electromyographic recordings from five superficial lumbo-pelvic muscles during a repetitive knee movement task. Trunk fat mass (from whole body-composition measurements) and movement accuracy as possible explanatory factors were included. Increased median frequency was observed in the lumbar erector spinae starting late in bed-rest, but this was not seen in its synergist, the thoracic erector spinae (p<.0001). These changes persisted up to 1-year after bed-rest and were independent of changes in body-composition or movement accuracy. Analysis suggested decreases of median frequency (p<.0001) in the abdominal and gluteal muscles to result from increased (p<.01) trunk fat levels during and after bed-rest. No changes in lumbo-pelvic muscle activation timing were seen. The results suggest that bed-rest particularly affects the shorter lumbar erector spinae and that the temporal sequencing of superficial lumbo-pelvic muscle activation is relatively robust.

Classification of team sport activities using a single wearable tracking device

Wearable tracking devices incorporating accelerometers and gyroscopes are increasingly being used for activity analysis in sports. However, minimal research exists relating to their ability to classify common activities. The purpose of this study was to determine whether data obtained from a single wearable tracking device can be used to classify team sport-related activities. Seventy-six non-elite sporting participants were tested during a simulated team sport circuit (involving stationary, walking, jogging, running, changing direction, counter-movement jumping, jumping for distance and tackling activities) in a laboratory setting. A MinimaxX S4 wearable tracking device was worn below the neck, in-line and dorsal to the first to fifth thoracic vertebrae of the spine, with tri-axial accelerometer and gyroscope data collected at 100Hz. Multiple time domain, frequency domain and custom features were extracted from each sensor using 0.5, 1.0, and 1.5s movement capture durations. Features were further screened using a combination of ANOVA and Lasso methods. Relevant features were used to classify the eight activities performed using the Random Forest (RF), Support Vector Machine (SVM) and Logistic Model Tree (LMT) algorithms. The LMT (79-92% classification accuracy) outperformed RF (32-43%) and SVM algorithms (27-40%), obtaining strongest performance using the full model (accelerometer and gyroscope inputs). Processing time can be reduced through feature selection methods (range 1.5-30.2%), however a trade-off exists between classification accuracy and processing time. Movement capture duration also had little impact on classification accuracy or processing time. In sporting scenarios where wearable tracking devices are employed, it is both possible and feasible to accurately classify team sport-related activities.

Vasodilatory effects of homologous adrenomedullin 2 and adrenomedullin 5 on isolated blood vessels of two species of eel

In mammals, adrenomedullin (AM) is a potent vasodilator through signalling pathways that involve the endothelium. In teleost fishes, a family of five AMs are present (AM1/4, AM2/3 and AM5) with four homologous AMs (AM1, AM2/3 and AM5) recently cloned from the Japanese eel, Anguilla japonica. Both AM2 and AM5 have been shown to be strong in vivo vasodepressors in eel, but the mechanism of action of homologous AMs on isolated blood vessels has not been examined in teleost fish. In this study, both eel AM2 and AM5 caused a marked vasodilation of the dorsal aorta. However, only AM5 consistently dilated the small gonadal artery in contrast to AM2 that had no effect in most preparations. Neither AM2 nor AM5 had any effect when applied to the first afferent branchial artery; in contrast, eel ANP always caused a large vasodilation of the branchial artery. In the dorsal aorta, indomethacin significantly reduced the AM2 vasodilation, but had no effect on the AM5 vasodilation. In contrast, removal of the endothelium significantly enhanced the AM5 vasodilation only. In the gonadal artery, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ) significantly reduced the AM5 vasodilation suggesting a role for soluble guanylyl cyclase in the dilation, but l-NNA and removal of the endothelium had no effect. The results of this study indicate that AM2 and AM5 have distinct vasodilatory effects that may be due to the peptides signalling via different receptors to regulate vascular tone in eel.