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The effects of different holding methods on heart rate (HR) changes in the green crab, Carcinus maenas (Linnaeus, 1758), were investigated. Green crabs were held in perforated plastic boxes (with or without a layer of sand) suspended above the bottom of the tank or strapped to a weighted plastic grate. The HR of green crabs classified as unrestrained (plastic box with or without sand) dropped more rapidly compared with restrained (hanging from band, strapped to grate) green crabs. Within 1 h, unrestrained green crabs exhibited periods of cardiac pausing accounting for between 8% and 14% of the hourly time. In contrast, restrained green crabs rarely exhibited cardiac pausing. When the green crabs were subjected to a temperature increase (10-30 [degrees]C), the HR of unrestrained green crabs reached higher levels than that of the restrained animals. The four restraining methods were also used to investigate cardiac responses to hypoxia. During progressive hypoxia (100%-20% oxygen), the HR of unrestrained green crabs declined to lower levels than that of the restrained animals. The restraining methods appeared to be more stressful for the green crabs that maintained elevated HRs and were less able to respond to environmental change compared with green crabs that could move freely within a small chamber. This suggests that even subtle changes in experimental design may alter physiological responses. Key words: green crab, Carcinus maenas, heart rate, temperature, hypoxia, restrained, unrestrained. Les effets de differentes methodes de retention sur les variations du rythme cardiaque (RC) de crabes verts, Carcinus maenas (Linnaeus, 1758), ont ete examines. Des crabes verts ont ete maintenus dans des boites en plastique perforees (avec ou sans couche de sable), suspendus par un elastique au-dessus de la base du reservoir ou fixes a l'aide d'elastiques a une grille en plastique lestee. Les RC de crabes verts classes comme etant non retenus (boite en plastique avec ou sans sable) ont baisse plus rapidement que ceux des crabes verts retenus (suspendus ou fixes a une grille). En l'espace de 1h, les crabes verts non retenus ont presente des periodes de pause cardiaque representant de 8% a 14% du temps horaire. En comparaison, les crabes verts retenus presentaient rarement des pauses cardiaques. Quand les crabes verts ont ete assujettis a une augmentation de la temperature (de 10 a 30 [degrees]C), les RC des crabes verts non retenus ont atteint des valeurs plus elevees que ceux des individus retenus. Les quatre methodes de retention ont aussi ete utilisees pour examiner les reactions cardiaques a l'hypoxie. Durant une hypoxie progressive (de 100% a 20% d'oxygene), les RC des crabes verts non retenus ont plus diminue que ceux des individus retenus. Les methodes de retention ont semble causer plus de stress aux crabes verts, qui ont maintenu des RC eleves et etaient moins en mesure de reagir a des changements ambiants que les crabes verts qui pouvaient se deplacer librement a l'interieur d'une petite enceinte. Ces resultats semblent indiquer que meme de legeres variations du schema experimental peuvent modifier les reactions physiologiques. [Traduit par la Redaction] Mots-cles: crabe vert, Carcinus maenas, rythme cardiaque, temperature, hypoxie, retenu, non retenu., Introduction Heart rate (HR) is used as a standard physiological measure in a wide variety of vertebrate and invertebrate taxa (e.g., DeFur and Mangum 1979; Davies and Morris 1993; von [...]

Background Near-infrared spectroscopy (NIRS)-based cerebral oximetry is a noninvasive technology used to estimate regional cerebral oxygen saturation (rSO.sub.2). Extracranial blood flow is known to substantially affect rSO.sub.2 values measured by most clinically available devices. Several studies have also reported that the Trendelenburg position and upright position have a larger effect on rSO.sub.2 measurements than the supine position. Therefore, we investigated the effect of these two positions (the Trendelenburg position versus the upright position) and extracranial contamination on rSO.sub.2 measurements obtained using two commercially available devices and one prototype device. Methods Twelve healthy volunteers were enrolled in the study. They each had three cerebral oximetry devices applied to their forehead (FORE-SIGHT ELITE[TM], CAS Medical Systems Inc., Branford, CT, USA; INVOS 5100c[TM], Medtronic, Minneapolis, MN, USA; and NIRO-TRS, Hamamatsu Photonics, Hamamatsu, Japan). A circumferential pneumatic head cuff was positioned proximal to the NIRS cerebral oximetry sensors. We measured rSO.sub.2, heart rate (HR), and blood pressure (BP) in six conditions (supine, Trendelenburg and upright positions, with and without scalp ischemia induced by head cuff inflation) every 5 min with each oximetry device. Total hemoglobin (tHb), which is associated with cerebral blood volume (CBV) as measured by positron emission tomography, was measured using the NIRO-TRS device to determine extracranial blood volume in each position. Results Measurements of rSO.sub.2 with all the devices were affected by extracranial contamination. The percentage of extracranial contamination was highest with INVOS 5100c[TM] in the upright position (INVOS, 21.3%; FORE-SIGHT, 14.3%; NIRO-TRS, 3.6%). Measurements of rSO.sub.2 obtained in the upright position were significantly lower than those obtained in the supine position, using INVOS-5100c[TM] and FORE-SIGHT ELITE[TM] (71 vs. 74% and 67 vs. 72%, respectively), but not using NIRO-TRS (62 vs. 64%). A significant decrease in tHb was observed after head cuff inflation in the supine and Trendelenburg positions (supine, 0.132-0.123 [mu]mol/l; Trendelenburg, 0.133-0.125 [mu]mol/l). Conclusions Except when using NIRO-TRS, measurements of rSO.sub.2 in the forehead are significantly lower when measured in the upright position than in the supine position. All devices in this study were affected by extracranial contamination., Author(s): Shinya Kato [sup.1] [sup.2] , Kenji Yoshitani [sup.1] [sup.2] , Yosuke Kubota [sup.1] , Yuzuru Inatomi [sup.1] , Yoshihiko Ohnishi [sup.1] Author Affiliations: (1) 0000 0004 0378 8307grid.410796.dDepartment of [...]

Background Elevated resting heart rate (HR) has emerged as a new risk factor for all-cause and cardiovascular mortality. The effect of marine-derived omega-3 long-chain polyunsaturated fatty acid (n-3 LCPUFAs) supplementation on HR was investigated as an outcome in many clinical trials. The present study was to provide an updated meta-analysis on the HR-slowing effect of n-3 LCPUFAs, and to differentiate the chronotropic effect between eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Methods PubMed and Cochrane databases were searched for relevant articles examining the effects of n-3 PUFAs on HR through May 2017. A random-effects model was used to generate the pooled effect sizes and 95% confidence intervals (CIs). The pooled effect sizes were presented as weighted mean differences (WMDs). Results A total of 51 randomized controlled trials (RCTs) with approximately 3000 participants were included in this meta-analysis. Compared to placebo, n-3 PUFA supplementation mildly but significantly reduced HR (-2.23 bpm; 95% CI: -3.07, -1.40 bpm). Moderate evidence of heterogeneity was observed among included trials (I.sup.2 = 49.1%, P heterogeneity < 0.001). When DHA and EPA were separately administered, modest HR reduction was observed in trials that supplemented with DHA (-2.47 bpm; 95% CI: -3.47, -1.46 bpm), but not in trials with EPA. Conclusions The present meta-analysis provides strong clinical evidence demonstrating the effect of heart rate reduction by n-3 LCPUFA supplementation. When DHA or EPA administered alone, heart rate was slowed by DHA rather than by EPA., Author(s): Khemayanto Hidayat [sup.1] , Jing Yang [sup.1] , Zheng Zhang [sup.1] , Guo-Chong Chen [sup.1] , Li-Qiang Qin [sup.1] , Manfred Eggersdorfer [sup.2] , Weiguo Zhang [sup.3] Author Affiliations: [...]