The Scientific World Journal: Physiology The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Comparative Performance of Hybrid and Elite Inbred Rice Varieties with respect to Their Source-Sink Relationship Thu, 29 Jan 2015 16:43:41 +0000 Hybrid rice varieties have higher yield potential over inbred varieties. This improvement is not always translated to the grain yield and its physiological causes are still unclear. In order to clarify it, two field experiments were conducted including two popular indica hybrids (BRRI hybrid dhan2 and Heera2) and one elite inbred (BRRI dhan45) rice varieties. Leaf area index, chlorophyll status, and photosynthetic rate of flag leaf, postheading crop growth rate, shoot reserve translocation, source-sink relation and yield, and its attributes of each variety were comprehensively analyzed. Both hybrid varieties outyielded the inbred. However, the hybrids and inbred varieties exhibited statistically identical yield in late planting. Both hybrids accumulated higher amount of biomass before heading and exhibited greater remobilization of assimilates to the grain in early plantings compared to the inbred variety. Filled grain (%) declined significantly at delayed planting in the hybrids compared to elite inbred due to increased temperature impaired-inefficient transport of assimilates. Flag leaf photosynthesis parameters were higher in the hybrid varieties than those of the inbred variety. Results suggest that greater remobilization of shoot reserves to the grain rendered higher yield of hybrid rice varieties. Md Moinul Haque, Habibur Rahman Pramanik, Jiban Krishna Biswas, K. M. Iftekharuddaula, and Mirza Hasanuzzaman Copyright © 2015 Md Moinul Haque et al. All rights reserved. Sauna-Induced Body Mass Loss in Young Sedentary Women and Men Wed, 31 Dec 2014 14:02:45 +0000 The aim of the study was to evaluate the relationship between body mass index (BMI) and body mass loss (BML) induced by thermal stress in a dry sauna. The study was conducted on a group of 674 sedentary students, 326 women and 348 men aged 19-20. The correlations between BMI scores and BML were determined. The subjects were placed in supine position in a dry sauna for two sessions of 10 minutes each with a 5-minute break. The influence of BMI on the amount of BML in the sauna was determined by nonlinear stepwise regression. The smallest BML was noted in underweight subjects; students with normal weight lost more weight, whereas the greatest BML was reported in overweight and obese subjects. Persons with a high BMI are at higher risk of dehydration, and they should pay particular attention to replenishing fluids during a visit to the sauna. The proposed equations for calculating BML based on a person's BMI can be useful in estimating the amount of fluids that should be replenished by both men and women during a visit to a dry sauna. Robert Podstawski, Tomasz Boraczyński, Michał Boraczyński, Dariusz Choszcz, Stefan Mańkowski, and Piotr Markowski Copyright © 2014 Robert Podstawski et al. All rights reserved. Median Preoptic Nucleus Mediates the Cardiovascular Recovery Induced by Hypertonic Saline in Hemorrhagic Shock Tue, 18 Nov 2014 09:39:11 +0000 Changes in plasma osmolarity, through central and peripheral osmoreceptors, activate the median preoptic nucleus (MnPO) that modulates autonomic and neuroendocrine adjustments. The present study sought to determine the participation of MnPO in the cardiovascular recovery induced by hypertonic saline infusion (HSI) in rats submitted to hemorrhagic shock. The recordings of mean arterial pressure (MAP) and renal vascular conductance (RVC) were carried out on male Wistar rats (250–300 g). Hemorrhagic shock was induced by blood withdrawal over 20 min until the MAP values of approximately 60 mmHg were attained. The nanoinjection (100 nL) of agonist (Muscimol 4 mM; experimental group (EXP)) or isotonic saline (NaCl 150 mM; control (CONT)) into MnPO was performed 2 min prior to intravenous overload of sodium through HSI (3 M NaCl, 1.8 mL/kg, b.wt.). Hemorrhagic shock reduced the MAP in control ( mmHg) and EXP ( mmHg) equipotently. The inhibition of MnPO impaired MAP (CONT: versus EXP:  mmHg) and RVC (CONT: versus EXP: ) recovery 10 min after HSI. The overall results in this study demonstrated, for the first time, that the MnPO plays an essential role in the HSI induced resuscitation during hypovolemic hemorrhagic shock. Nathalia Oda Amaral, Lara Marques Naves, Marcos Luiz Ferreira-Neto, André Henrique Freiria-Oliveira, Eduardo Colombari, Daniel Alves Rosa, Angela Adamski da Silva Reis, Danielle Ianzer, Carlos Henrique Xavier, and Gustavo Rodrigues Pedrino Copyright © 2014 Nathalia Oda Amaral et al. All rights reserved. Repeated High Intensity Bouts with Long Recovery: Are Bicarbonate or Carbohydrate Supplements an Option? Mon, 10 Nov 2014 06:05:37 +0000 The effects of varying recovery modes and the influence of preexercise sodium bicarbonate and carbohydrate ingestion on repeated high intensity performance, acid-base response, and recovery were analyzed in 12 well-trained males. They completed three repeated high intensity running bouts to exhaustion with intervening recovery periods of 25 min under the following conditions: sodium bicarbonate, active recovery (BIC); carbohydrate ingestion, active recovery (CHO); placebo ingestion, active recovery (ACTIVE); placebo ingestion, passive recovery (PASSIVE). Blood lactate (BLa), blood gases, heart rate, and time to exhaustion were collected. The three high intensity bouts had a duration of , and  s demonstrating a decrease from bout 1 to bout 3. Supplementation strategy had no effect on performance in the first bout, even with differences in pH and bicarbonate (HC). Repeated sprint performance was not affected by supplementation strategy when compared to ACTIVE, while PASSIVE resulted in a more pronounced decrease in performance compared with all other interventions. BIC led to greater BLa, pH, and HC values compared with all other interventions, while for PASSIVE the opposite was found. BLa recovery was lowest in PASSIVE; recovery in pH, and HC was lower in PASSIVE and higher in BIC. Thomas Stöggl, Rafael Torres-Peralta, Ebru Cetin, and Masaru Nagasaki Copyright © 2014 Thomas Stöggl et al. All rights reserved. Grooming Behavior in American Cockroach is Affected by Novelty and Odor Tue, 21 Oct 2014 13:02:46 +0000 The main features of grooming behavior are amazingly similar among arthropods and land vertebrates and serve the same needs. A particular pattern of cleaning movements in cockroaches shows cephalo-caudal progression. Grooming sequences become longer after adaptation to the new setting. Novelty related changes in grooming are recognized as a form of displacement behavior. Statistical analysis of behavior revealed that antennal grooming in American cockroach, Periplaneta americana L., was significantly enhanced in the presence of odor. Marianna I. Zhukovskaya Copyright © 2014 Marianna I. Zhukovskaya. All rights reserved. Effect of Lower Body Compression Garments on Hemodynamics in Response to Running Session Mon, 18 Aug 2014 07:25:54 +0000 Purpose. Compression garments are often worn during exercise and allegedly have ergogenic and/or physiological effects. In this study, we compared hemodynamics and running performance while wearing compression and loose-fit breeches. We hypothesized that in neutral-warm environment compression breeches impair performance by diminishing body cooling via evaporative sweat loss and redistributing blood from active musculature to skin leading to a larger rise in body temperature and prolonging recovery of hemodynamics after exercise. Methods. Changes in hemodynamics (leg blood flow, heart rate, and blood pressure during orthoclinostatic test), calf muscle tissue oxygenation, and skin and core temperatures were measured in response to 30 min running (simulation of aerobic training session) followed by maximal 400 m sprint (evaluation of running performance) in recreationally active females  yrs;  kg) wearing compression or loose-fit breeches in randomized fashion. Results. Wearing compression breeches resulted in larger skin temperature rise under the garment during exercise and recovery (by about 1°C, ; statistical power > 85%), while core temperature dynamics and other measured parameters including circulation, running performance, and sensations were similar compared to wearing loose-fit breeches . Conclusion. Compared with loose-fit breeches, compression breeches have neither positive nor negative physiological and performance effects for females running in thermoneutral environment. Tomas Venckūnas, Eugenijus Trinkūnas, Sigitas Kamandulis, Jonas Poderys, Albinas Grūnovas, and Marius Brazaitis Copyright © 2014 Tomas Venckūnas et al. All rights reserved. Silicon Application Increases Drought Tolerance of Kentucky Bluegrass by Improving Plant Water Relations and Morphophysiological Functions Sun, 29 Jun 2014 00:00:00 +0000 Drought stress encumbers the growth of turfgrass principally by disrupting the plant-water relations and physiological functions. The present study was carried out to appraise the role of silicon (Si) in improving the drought tolerance in Kentucky bluegrass (Poa pratensis L.). Drought stress and four levels (0, 200, 400, and 800 mg L−1) of Si (Na2SiO39H2O) were imposed after 2 months old plants cultured under glasshouse conditions. Drought stress was found to decrease the photosynthesis, transpiration rate, stomatal conductance, leaf water content, relative growth rate, water use efficiency, and turf quality, but to increase in the root/shoot and leaf carbon/nitrogen ratio. Such physiological interferences, disturbances in plant water relations, and visually noticeable growth reductions in Kentucky bluegrass were significantly alleviated by the addition of Si after drought stress. For example, Si application at 400 mg L−1 significantly increased the net photosynthesis by 44%, leaf water contents by 33%, leaf green color by 42%, and turf quality by 44% after 20 days of drought stress. Si application proved beneficial in improving the performance of Kentucky bluegrass in the present study suggesting that manipulation of endogenous Si through genetic or biotechnological means may result in the development of drought resistance in grasses. Shah Saud, Xin Li, Yang Chen, Lu Zhang, Shah Fahad, Saddam Hussain, Arooj Sadiq, and Yajun Chen Copyright © 2014 Shah Saud et al. All rights reserved. Induction of Resistance Mediated by an Attenuated Strain of Valsa mali var. mali Using Pathogen-Apple Callus Interaction System Wed, 25 Jun 2014 13:19:02 +0000 To study the induced resistance in apple against Valsa mali var. mali (Vmm), a Vmm–apple callus interaction system was developed to evaluate the induced resistance of an attenuated Vmm strain LXS081501 against further infection by a virulent Vmm strain LXS080601. The infection index was up to 97.32 for apple calli inoculated with LXS080601 alone at 15 days after inoculation whereas it was only 41.84 for calli pretreated with LXS081501 followed by LXS080601 inoculation. In addition, the maximum levels of free proline, soluble sugar, and protein in calli treated with LXS081501 plus LXS080601 were 2.14 to 3.47 times higher than controls and 1.42 to 1.75 times higher than LXS080601 treatment. The activities of defense-related enzymes such as phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD), and catalase (CAT) as well as β-1,3-glucanase and chitinase in apple calli inoculated with LXS080601 alone or LXS081501 plus LXS080601 increased significantly 24 hai and peaked from 48 to 120 hpi. However, in the latter treatment, the maximum enzyme activities were much higher and the activities always maintained much higher levels than control during the experimental period. These results suggested the roles of osmotic adjustment substances and defense-related enzymes in induced resistance. Qingming Zhang, Caixia Wang, Daojing Yong, Guifang Li, Xiangli Dong, and Baohua Li Copyright © 2014 Qingming Zhang et al. All rights reserved. Screening of Purslane (Portulaca oleracea L.) Accessions for High Salt Tolerance Mon, 09 Jun 2014 00:00:00 +0000 Purslane (Portulaca oleracea L.) is an herbaceous leafy vegetable crop, comparatively more salt-tolerant than any other vegetables with high antioxidants, minerals, and vitamins. Salt-tolerant crop variety development is of importance due to inadequate cultivable land and escalating salinity together with population pressure. In this view a total of 25 purslane accessions were initially selected from 45 collected purslane accessions based on better growth performance and subjected to 5 different salinity levels, that is, 0.0, 10.0, 20.0, 30.0, and 40.0 dS m−1 NaCl. Plant height, number of leaves, number of flowers, and dry matter contents in salt treated purslane accessions were significantly reduced () and the enormity of reduction increased with increasing salinity stress. Based on dry matter yield reduction, among all 25 purslane accessions 2 accessions were graded as tolerant (Ac7 and Ac9), 6 accessions were moderately tolerant (Ac3, Ac5, Ac6, Ac10, Ac11, and Ac12), 5 accessions were moderately susceptible (Ac1, Ac2, Ac4, Ac8, and Ac13), and the remaining 12 accessions were susceptible to salinity stress and discarded from further study. The selected 13 purslane accessions could assist in the identification of superior genes for salt tolerance in purslane for improving its productivity and sustainable agricultural production. Md. Amirul Alam, Abdul Shukor Juraimi, M. Y. Rafii, Azizah Abdul Hamid, and Farzad Aslani Copyright © 2014 Md. Amirul Alam et al. All rights reserved. A Possible Change Process of Inflammatory Cytokines in the Prolonged Chronic Stress and Its Ultimate Implications for Health Tue, 03 Jun 2014 06:55:58 +0000 Sustained stress triggers series of changes in the brain and the body. At the early stage of stress, the activated hypothalamus-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) axis can upregulate the levels of glucocorticoid (GCs) and catecholamines (CAs), respectively, and then they in turn inhibit the secretion of proinflammatory cytokines directly or indirectly while promoting the secretion of anti-inflammatory cytokines. At the prolonged stage, the sustained activated HPA demonstrates cortisol-resistance. At the same time, the inflammation related transcription pathway, such as nuclear-factor kappa-B (NF-κB) signaling, may be inhibited. Additionally, the inflammatory cytokines mediate a negative feedback regulation on themselves. Collectively, these regulations may increase the proinflammatory cytokines while decreasing the anti-inflammatory cytokines. This may further activate NF-κB and increase the proinflammation cytokines, which in turn reduce the inflammatory responses, contributing to various diseases. Rui Tian, Gonglin Hou, Dan Li, and Ti-Fei Yuan Copyright © 2014 Rui Tian et al. All rights reserved. How Fast Is Recovery of Impaired Glucose Tolerance after 21-Day Bed Rest (NUC Study) in Healthy Adults? Tue, 11 Mar 2014 07:23:52 +0000 Aim. We hypothesized that 4 days of normal daily activity after 21 days of experimental bed rest (BR) will not reverse BR induced impaired glucose tolerance. Design. Glucose tolerance of seven male, healthy, untrained test subjects (age: 27.6 (3.3) years (mean (SD)); body mass: 78.6 (6.4) kg; height: 1.81 (0.04) m; VO2 max: 39.5 (5.4) ml/kg body mass/min) was studied. They stayed twice in the metabolic ward (crossover design), 21 days in bed and 7 days before and after BR each. Oral glucose tolerance tests were applied before, on day 21 of BR, and 5 and 14 days after BR. Results. On day 21 of BR, AUC120 min of glucose concentration was increased by 28.8 (5.2)% and AUC120 min of insulin by 35.9 (10.2)% (glucose: ; insulin: ). Fourteen days after BR, AUC120 min of serum insulin concentrations returned to pre-bed-rest concentrations () and AUC120 min of glucose was still higher (). Insulin resistance did not change, but sensitivity index was reduced during BR (). Conclusion. Four days of light physical workload does not compensate inactivity induced impaired glucose tolerance. An individually tailored and intensified training regime is mandatory in patients being in bed rest to get back to normal glucose metabolism in a reasonable time frame. Martina Heer, Natalie Baecker, Stephan Wnendt, Annelie Fischer, Gianni Biolo, and Petra Frings-Meuthen Copyright © 2014 Martina Heer et al. All rights reserved. The Relationship between Climbing Ability and Physiological Responses to Rock Climbing Mon, 27 Jan 2014 19:15:00 +0000 Aim. The aim of this study was to examine the relationship between submaximal and maximal physiological responses to rock climbing for climbers of differing abilities. Methods. Twenty-six male climbers performed a submaximal climbing test on a known circuit at 90° (vertical) and 105° (15° overhanging) inclination and speed 25 movements·min−1. A maximal test was undertaken on a similar circuit at the same speed with inclination increasing by 10° for each successive 3 min stage. Results. Mean oxygen consumption and heart rate (HR) increased with wall inclination and climbers reached a mean (±SD) peak of 40.3 ± 3.5 mL·kg−1·min−1 during the maximal test. Self-reported climbing ability was negatively correlated with and HR during the submaximal test at 90° (, ; HR, and ) and at 105° (, ; HR, and ) suggesting an increased exercise economy for climbers with a higher ability level. Conclusion. Findings from this study indicate that there is a relationship between wall inclination and the physiological demand of a climb. However, the increased technical ability and fitness of higher level climbers appears to an extent to offset the increased demand through improved exercise economy which in turn leads to an increased time to exhaustion and an improvement in performance. Jiří Baláš, Michaela Panáčková, Barbora Strejcová, Andrew J. Martin, Darryl J. Cochrane, Miloš Kaláb, Jan Kodejška, and Nick Draper Copyright © 2014 Jiří Baláš et al. All rights reserved. Role of Relative Humidity in Processing and Storage of Seeds and Assessment of Variability in Storage Behaviour in Brassica spp. and Eruca sativa Mon, 30 Dec 2013 14:23:54 +0000 The role of relative humidity (RH) while processing and storing seeds of Brassica spp. and Eruca sativa was investigated by creating different levels of relative humidity, namely, 75%, 50%, 32%, and 11% using different saturated salt solutions and 1% RH using concentrated sulphuric acid. The variability in seed storage behaviour of different species of Brassica was also evaluated. The samples were stored at in sealed containers and various physiological parameters were assessed at different intervals up to three months. The seed viability and seedling vigour parameters were considerably reduced in all accessions at high relative humidity irrespective of the species. Storage at intermediate relative humidities caused minimal decline in viability. All the accessions performed better at relative humidity level of 32% maintaining seed moisture content of 3%. On analyzing the variability in storage behaviour, B. rapa and B. juncea were better performers than B. napus and Eruca sativa. A. Suma, Kalyani Sreenivasan, A. K. Singh, and J. Radhamani Copyright © 2013 A. Suma et al. All rights reserved. Alterations in Red Blood Cells and Plasma Properties after Acute Single Bout of Exercise Wed, 18 Dec 2013 12:06:05 +0000 The aim of this study was to investigate alterations in haemoglobin conformation and parameters related to oxidative stress in whole erythrocytes, membranes, and plasma after a single bout of exercise in a group of young untrained men. Venous blood samples from eleven healthy young untrained males (age = 22 ± 2 years, BMI = 23 ± 2.5 kg/m2) were taken from the antecubital vein before an incremental cycling exercise test, immediately after exercise, and 1 hour after exercise. Individual heart rate response to this exercise was 195 ± 12 beats/min and the maximum wattage was 292 ± 27 W. Immediately after exercise, significant increase in standard parameters (haemoglobin, haematocrit, lactate levels, and plasma volume) of blood was observed as well as plasma antioxidant capacity one hour after exercise. Reversible conformational changes in haemoglobin, measured using a maleimide spin label, were found immediately following exercise. The concentration of ascorbic acid inside erythrocytes significantly decreased after exercise. A significant decline in membrane thiols was observed one hour after exercise, but simultaneously an increase in plasma thiols immediately after and 1 h after exercise was also observed. This study shows that a single bout of exercise can lead to mobilization of defensive antioxidant systems in blood against oxidative stress in young untrained men. Krzysztof Gwozdzinski, Anna Pieniazek, Joanna Brzeszczynska, Sabina Tabaczar, and Anna Jegier Copyright © 2013 Krzysztof Gwozdzinski et al. All rights reserved. Demographic Characteristics of World Class Jamaican Sprinters Tue, 10 Dec 2013 16:01:45 +0000 The dominance of Jamaican sprinters in international meets remains largely unexplained. Proposed explanations include demographics and favorable physiological characteristics. The aim of this study was to analyze the demographic characteristics of world class Jamaican sprinters. Questionnaires administered to 120 members of the Jamaican national team and 125 controls elicited information on place of birth, language, ethnicity, and distance and method of travel to school. Athletes were divided into three groups based on athletic disciplines: sprint (s: 100–400 m; ), jump and throw (j/t: jump and throw; ) and, middle distance (md: 800–3000 m; ). Frequency differences between groups were assessed using chi-square tests. Regional or county distribution of sprint differed from that of middle distance () but not from that of jump and throw athletes () and that of controls (). Sprint athletes predominately originated from the Surrey county (s = 46%, j/t = 37%, md = 17, C = 53%), whilst middle distance athletes exhibited excess from the Middlesex county (md = 60%). The language distribution of all groups showed uniformity with a predominance of English. A higher proportion of middle distance and jump and throw athletes walked to school (md = 80%, j/t = 52%, s = 10%, and C = 12%) and travelled greater distances to school. In conclusion, Jamaica’s success in sprinting may be related to environmental and social factors. Rachael Irving, Vilma Charlton, Errol Morrison, Aldeam Facey, and Oral Buchanan Copyright © 2013 Rachael Irving et al. All rights reserved. A High-Fat Diet Enriched with Low Omega-6 to Omega-3 Fatty Acid Ratio Reduced Fat Cellularity and Plasma Leptin Concentration in Sprague-Dawley Rats Wed, 30 Oct 2013 11:45:52 +0000 This study was aimed to investigate the effects of dietary fatty acids on the accretion pattern of major fat pads, inguinal fat cellularity, and their relation with plasma leptin concentration. Forty Sprague-Dawley rats were randomly assigned into four groups and received the following diets for 22 weeks: (1) standard rat chow diet (CTRL), (2) CTRL + 10% (w/w) butter (HFAR), (3) CTRL + 3.33% (w/w) menhaden fish oil + 6.67% (w/w) soybean oil (MFAR), and (4) CTRL + 6.67% (w/w) menhaden fish oil + 3.33% (w/w) soybean oil (LFAR). Inguinal fat cellularity and plasma leptin concentration were measured in this study. Results for inguinal fat cellularity showed that the mean adipocyte number for the MFAR (9.2  105 ± 3.6) and LFAR (8.5  105 ± 5.1) groups was significantly higher () than the rest, while the mean adipocyte diameter of HFAR group was larger () (46.2 ± 2.8) than the rest. The plasma leptin concentration in the HFAR group was higher () (3.22 ± 0.32 ng/mL), than the other groups. The higher inguinal fat cellularity clearly indicated the ability of the polyunsaturated fatty acids (PUFA) and butter supplemented diets to induce hyperplasia and hypertrophy of fat cells, respectively, which caused adipocyte remodeling due to hyperleptinemia. A. W. Tekeleselassie, Y. M. Goh, M. A. Rajion, M. Motshakeri, and M. Ebrahimi Copyright © 2013 A. W. Tekeleselassie et al. All rights reserved. Relationship between Repeated Sprint Ability and Aerobic Capacity in Professional Soccer Players Tue, 01 Oct 2013 13:29:29 +0000 Aim. The aim of the present study was to investigate the relationship between maximal aerobic capacity () and repeated sprint ability (RSA) in a group of professional soccer players. Methods. Forty-one professional soccer players (age  yrs, height  cm, weight  kg) were required to perform tests to assess RSA and on two separate days with at least 48 hr rest between testing sessions. Each player performed a treadmill test to determine their and a test for RSA involving the players completing  m sprints (turn after 20 m) with 20 s active recovery between each sprint. Results. There was a significant negative correlation between body mass normalised and mean sprint time () (; ) and total sprint time () (, ). Conclusion. Results of the current study indicate that is one important factor aiding soccer players in the recovery from repeated sprint type activities. Rhys M. Jones, Christian C. Cook, Liam P. Kilduff, Zoran Milanović, Nic James, Goran Sporiš, Bruno Fiorentini, Fredi Fiorentini, Anthony Turner, and Goran Vučković Copyright © 2013 Rhys M. Jones et al. All rights reserved. Oxygen Uptake in Maximal Effort Constant Rate and Interval Running Sun, 01 Sep 2013 08:47:39 +0000 This study investigated differences in average of maximal effort interval running to maximal effort constant rate running at lactate threshold matched for time. The average and distance covered of 10 recreational male runners (: 4158 ± 390 mL·min−1) were compared between a maximal effort constant-rate run at lactate threshold (CRLT), a maximal effort interval run (INT) consisting of 2 min at speed with 2 minutes at 50% of repeated 5 times, and a run at the average speed sustained during the interval run (CR submax). Data are presented as mean and 95% confidence intervals. The average for INT, 3451 (3269–3633) mL·min−1, 83% , was not significantly different to CRLT, 3464 (3285–3643) mL·min−1, 84% , but both were significantly higher than CR sub-max, 3464 (3285–3643) mL·min−1, 76% . The distance covered was significantly greater in CLRT, 4431 (4202–3731) metres, compared to INT and CR sub-max, 4070 (3831–4309) metres. The novel finding was that a 20-minute maximal effort constant rate run uses similar amounts of oxygen as a 20-minute maximal effort interval run despite the greater distance covered in the maximal effort constant-rate run. Daniel Pratt, Brendan J. O'Brien, and Bradley Clark Copyright © 2013 Daniel Pratt et al. All rights reserved. Response of Rice Nitrogen Physiology to High Nighttime Temperature during Vegetative Stage Wed, 28 Aug 2013 13:53:34 +0000 The effects of night temperature on plant morphology and nitrogen accumulation were examined in rice (Oryza sativa L.) during vegetative growth. The results showed that the shoot biomass of the plants was greater at 27°C (high nighttime temperature, HNT) than at 22°C (CK). However, the increase in both shoot and root biomasses was not significant under 10 mg N/L. The shoot nitrogen concentrations were 16.1% and 16.7% higher in HNT than in CK under 160 and 40 mg N/L. These results suggest that plant N uptake was enhanced under HNT; however, the positive effect might be limited by the N status of the plants. In addition, leaf area, plant height, root maximum length, root and shoot nitrogen concentrations, soluble leaf protein content, and soluble leaf carbohydrate content were greater in HNT than in CK under 40 and 160 mg N/L, while fresh root volume, root number, and the content of free amino acid in leaf were not significantly different between HNT and CK regardless of nitrogen levels. Moreover, leaf GS activity under HNT was increased at 160 mg N/L compared with that under CK, which might partly explain the positive effect of HNT on soluble protein and carbohydrate content. Song Chen, Xiaoguo Zhang, Xia Zhao, Danying Wang, Chunmei Xu, Chenglin Ji, and Xiufu Zhang Copyright © 2013 Song Chen et al. All rights reserved. Cardiac Electrophysiology Tue, 20 Aug 2013 11:09:12 +0000 Yanggan Wang, Yimei Du, and Xun Ai Copyright © 2013 Yanggan Wang et al. All rights reserved. Effects of Low-Level Autonomic Stimulation on Prevention of Atrial Fibrillation Induced by Acute Electrical Remodeling Thu, 20 Jun 2013 17:10:19 +0000 Background. Rapid atrial pacing (RAP) can induce electrical and autonomic remodeling and facilitate atrial fibrillation (AF). Recent reports showed that low-level vagosympathetic nerve stimulation (LLVNS) can suppress AF, as an antiarrhythmic effect. We hypothesized that LLVNS can reverse substrate heterogeneity induced by RAP. Methods and Results. Mongrel dogs were divided into (LLVNS+RAP) and RAP groups. Electrode catheters were sutured to multiple atrial sites, and LLVNS was applied to cervical vagosympathetic trunks with voltage 50% below the threshold slowing sinus rate by ⩽30 msec. RAP induced a significant decrease in effective refractory period (ERP) and increase in the window of vulnerability at all sites, characterized by descending and elevated gradient differences towards the ganglionic plexi (GP) sites, respectively. The ERP dispersion was obviously enlarged by RAP and more significant when the ERP of GP-related sites was considered. Recovery time from AF was also prolonged significantly as a result of RAP. LLVNS could reverse all these changes induced by RAP and recover the heterogeneous substrate to baseline. Conclusions. LLVNS can reverse the electrical and autonomic remodeling and abolish the GP-central gradient differences induced by RAP, and thus it can recover the homogeneous substrate, which may be the underlying mechanism of its antiarrhythmic effect. Yubi Lin, Ning Bian, Hairui Li, Jia Chen, Huijie Xing, Hong Li, Dandan Huang, Xianwu Lan, Bojun Gong, Li Zhou, Ruijie Liu, Min Guan, Dongdong Zhang, Gang Du, Zhengyi Huang, Xiaoming Chen, Tao Zhang, Jianyi Feng, Shaorong Wu, Liwei Wang, Aidong Zhang, and Zicheng Li Copyright © 2013 Yubi Lin et al. All rights reserved. Skeletal Muscle Physiology Thu, 06 Jun 2013 12:21:46 +0000 Lucas Guimarães-Ferreira, Humberto Nicastro, Jacob Wilson, and Nelo Eidy Zanchi Copyright © 2013 Lucas Guimarães-Ferreira et al. All rights reserved. Metabolic Disturbance in PCOS: Clinical and Molecular Effects on Skeletal Muscle Tissue Wed, 05 Jun 2013 14:27:29 +0000 Polycystic ovary syndrome is a complex hormonal disorder affecting the reproductive and metabolic systems with signs and symptoms related to anovulation, infertility, menstrual irregularity and hirsutism. Skeletal muscle plays a vital role in the peripheral glucose uptake. Since PCOS is associated with defects in the activation and pancreatic dysfunction of β-cell insulin, it is important to understand the molecular mechanisms of insulin resistance in PCOS. Studies of muscle tissue in patients with PCOS reveal defects in insulin signaling. Muscle biopsies performed during euglycemic hyperinsulinemic clamp showed a significant reduction in glucose uptake, and insulin-mediated IRS-2 increased significantly in skeletal muscle. It is recognized that the etiology of insulin resistance in PCOS is likely to be as complicated as in type 2 diabetes and it has an important role in metabolic and reproductive phenotypes of this syndrome. Thus, further evidence regarding the effect of nonpharmacological approaches (e.g., physical exercise) in skeletal muscle of women with PCOS is required for a better therapeutic approach in the management of various metabolic and reproductive problems caused by this syndrome. Wagner Silva Dantas, Bruno Gualano, Michele Patrocínio Rocha, Cristiano Roberto Grimaldi Barcellos, Viviane dos Reis Vieira Yance, and José Antonio Miguel Marcondes Copyright © 2013 Wagner Silva Dantas et al. All rights reserved. Polymorphisms but Not Mutations of the KCNQ1 Gene Are Associated with Lone Atrial Fibrillation in the Chinese Han Population Thu, 18 Apr 2013 14:21:35 +0000 Background. Recent studies suggest that mutation of the slow delayed rectifier potassium channel (IKs) contributes to familial atrial fibrillation (FAF). In the current study, we identified common genetic variants of KCNQ1 and explored the potential association between KCNQ1 polymorphism with lone AF (LAF). Methods. Clinical data and blood samples were collected from 190 Han Chinese patients with sporadic AF and matched healthy controls. Variants of the KCNQ1 gene were identified using single-strand conformational polymorphism (SSCP) analysis. A case-control association study in KCNQ1 identified six known single-nucleotide polymorphisms (SNPs) during SSCP screening of the 190 LAF patients and 190 healthy controls. Results. One of the SNPs in KCNQ1 was strongly associated with LAF; significant allelic association was detected rs59233444 (, , 95% confidence interval (CI): 1.083–1.993). A multiple regression analysis indicated that rs59233444 is an independent risk factor for LAF. Twelve new variants were identified in KCNQ1, including one in the 5′-UTR, two in the 3′-UTR, six in introns, two synonymous substitutions, and one missense substitution. Variants c.1009C>T, c.1860C>T, and c.+2285C>T were not present in the 190 controls, and the others were identified in controls at various frequencies. Conclusions. rs59233444, a common SNP but not mutation in the coding regions of the KCNQ1 gene, is a risk factor for LAF in Chinese Han population. Hui-min Chu, Ming-jun Feng, Yi-gang Li, Yi-xin Zhang, Ji-fang Ma, Bin He, Yi-bo Yu, Jing Liu, and Xiao-min Chen Copyright © 2013 Hui-min Chu et al. All rights reserved. Calcium Transient and Sodium-Calcium Exchange Current in Human versus Rabbit Sinoatrial Node Pacemaker Cells Mon, 25 Mar 2013 10:10:22 +0000 There is an ongoing debate on the mechanism underlying the pacemaker activity of sinoatrial node (SAN) cells, focusing on the relative importance of the “membrane clock” and the “ clock” in the generation of the small net membrane current that depolarizes the cell towards the action potential threshold. Specifically, the debate centers around the question whether the membrane clock-driven hyperpolarization-activated current, , which is also known as the “funny current” or “pacemaker current,” or the Ca2+ clock-driven sodium-calcium exchange current, , is the main contributor to diastolic depolarization. In our contribution to this journal’s “Special Issue on Cardiac Electrophysiology,” we present a numerical reconstruction of and in isolated rabbit and human SAN pacemaker cells based on experimental data on action potentials, , and intracellular calcium concentration () that we have acquired from these cells. The human SAN pacemaker cells have a smaller , a weaker transient, and a smaller than the rabbit cells. However, when compared to the diastolic net membrane current, is of similar size in human and rabbit SAN pacemaker cells, whereas is smaller in human than in rabbit cells. Arie O. Verkerk, Marcel M. G. J. van Borren, and Ronald Wilders Copyright © 2013 Arie O. Verkerk et al. All rights reserved. Predictors of Cardiac Resynchronization Therapy Response: The Pivotal Role of Electrocardiogram Wed, 20 Mar 2013 10:42:44 +0000 Heart failure affects millions of patients all over the world, and its treatment is a major clinical challenge. Cardiac dyssynchrony is common among patients with advanced heart failure. Resynchronization therapy is a major advancement in heart failure management, but unfortunately not all patients respond to this therapy. Hence, many diagnostic tests have been used to predict the response and prognosis after cardiac resynchronization therapy. In this paper we summarize the usefulness of different diagnostic modalities with special emphasis on the role of surface electrocardiogram as a major predictor of response to cardiac resynchronization therapy. Yahya S. Al Hebaishi, Halia Z. Al Shehri, and Abdulrahman M. Al Moghairi Copyright © 2013 Yahya S. Al Hebaishi et al. All rights reserved. Mechanism of and Therapeutic Strategy for Atrial Fibrillation Associated with Diabetes Mellitus Thu, 14 Mar 2013 08:43:00 +0000 Diabetes mellitus (DM) is one of the most important risk factors for atrial fibrillation (AF) and is a predictor of stroke and thromboembolism. DM may increase the incidence of AF, and when it is combined with other risk factors, the incidence of stroke and thromboembolism may also be higher; furthermore, hospitalization due to heart failure appears to increase. Maintenance of well-controlled blood glucose and low levels of HbA1c in accordance with guidelines may decrease the incidence of AF. The mechanisms of AF associated with DM are autonomic remodeling, electrical remodeling, structural remodeling, and insulin resistance. Inhibition of the renin-angiotensin system is suggested to be an upstream therapy for this type of AF. Studies have indicated that catheter ablation may be effective for AF associated with DM, restoring sinus rhythm and improving prognosis. Catheter ablation combined with hypoglycemic agents may further increase the rate of maintenance of sinus rhythm and reduce the need for reablation. Yubi Lin, Hairui Li, Xianwu Lan, Xianghui Chen, Aidong Zhang, and Zicheng Li Copyright © 2013 Yubi Lin et al. All rights reserved. Substrains of Inbred Mice Differ in Their Physical Activity as a Behavior Wed, 06 Mar 2013 15:29:27 +0000 Recent studies strengthen the belief that physical activity as a behavior has a genetic basis. Screening wheel-running behavior in inbred mouse strains highlighted differences among strains, showing that even very limited genetic differences deeply affect mouse behavior. We extended this observation to substrains of the same inbred mouse strain, that is, BALB/c mice. We found that only a minority of the population of one of these substrains, the BALB/c J, performs spontaneous physical activity. In addition, the runners of this substrain cover a significantly smaller distance than the average runners of two other substrains, namely, the BALB/c ByJ and the BALB/c AnNCrl. The latter shows a striking level of voluntary activity, with the average distance run/day reaching up to about 12 kilometers. These runners are not outstanders, but they represent the majority of the population, with important scientific and economic fallouts to be taken into account during experimental planning. Spontaneous activity persists in pathological conditions, such as cancer-associated cachexia. This important amount of physical activity results in a minor muscle adaptation to endurance exercise over a three-week period; indeed, only a nonsignificant increase in NADH transferase+ fibers occurs in this time frame. Dario Coletti, Emanuele Berardi, Paola Aulino, Eleonora Rossi, Viviana Moresi, Zhenlin Li, and Sergio Adamo Copyright © 2013 Dario Coletti et al. All rights reserved. Improved Tissue Culture Conditions for Engineered Skeletal Muscle Sheets Thu, 28 Feb 2013 13:19:04 +0000 The potential clinical utility of engineered muscle is currently restricted by limited in vitro capacity of expanded muscle precursor cells to fuse and form mature myofibers. The purpose of this study was to use isotropic skeletal muscle sheets to explore the impact of (1) fibroblast coculture and (2) fibroblast-conditioned media (fCM) on in vitro myogenesis. Muscle sheets were prepared by seeding varying ratios of skeletal myoblasts and fibroblasts on a biomimetic substrate and culturing the resulting tissue in either control media or fCM. Muscle sheets were prepared from two cell subpopulations, (1) C2C12 and NOR-10 and (2) primary neonatal rat skeletal muscle cells (nSKM). In C2C12/Nor-10 muscle sheets fCM conferred a myogenic advantage early in culture; at D1 a statistically significant 3.12 ± 0.8-fold increase in myofiber density was observed with fCM. A high purity satellite cell population was collected from an initially mixed population of nSKMs via cell sorting for positive α7-integrin expression. On D6, tissue sheets with low fibroblast concentrations (0 & 10%) cultured in fCM had increased average myofiber density (4.8 ± 0.2 myofibers/field) compared to tissue sheets with high fibroblast concentrations (50%) cultured in control media (1.0 ± 0.1 myofibers/field). Additionally, fCM promoted longer, thicker myofibers with a mature phenotype. Sara Hinds, Natalia Tyhovych, Clint Sistrunk, and Louis Terracio Copyright © 2013 Sara Hinds et al. All rights reserved. Cytokine Response of Cultured Skeletal Muscle Cells Stimulated with Proinflammatory Factors Depends on Differentiation Stage Wed, 20 Feb 2013 16:12:00 +0000 Myoblast proliferation and myotube formation are critical early events in skeletal muscle regeneration. The attending inflammation and cytokine signaling are involved in regulation of skeletal muscle cell proliferation and differentiation. Secretion of muscle-derived cytokines upon exposure to inflammatory factors may depend on the differentiation stage of regenerating muscle cells. Cultured human myoblasts and myotubes were exposed to 24-hour treatment with tumor necrosis factor (TNF)-α or lipopolysaccharide (LPS). Secretion of interleukin 6 (IL-6), a major muscle-derived cytokine, and interleukin 1 (IL-1), an important regulator of inflammatory response, was measured 24 hours after termination of TNF-α or LPS treatment. Myoblasts pretreated with TNF-α or LPS displayed robustly increased IL-6 secretion during the 24-hour period after removal of treatments, while IL-1 secretion remained unaltered. IL-6 secretion was also increased in myotubes, but the response was less pronounced compared with myoblasts. In contrast to myoblasts, IL-1 secretion was markedly stimulated in LPS-pretreated myotubes. We demonstrate that preceding exposure to inflammatory factors stimulates a prolonged upregulation of muscle-derived IL-6 and/or IL-1 in cultured skeletal muscle cells. Our findings also indicate that cytokine response to inflammatory factors in regenerating skeletal muscle partially depends on the differentiation stage of myogenic cells. Matej Podbregar, Mitja Lainscak, Oja Prelovsek, and Tomaz Mars Copyright © 2013 Matej Podbregar et al. All rights reserved. Exercise-Induced Rhabdomyolysis and Stress-Induced Malignant Hyperthermia Events, Association with Malignant Hyperthermia Susceptibility, and RYR1 Gene Sequence Variations Sun, 10 Feb 2013 16:06:42 +0000 Exertional rhabdomyolysis (ER) and stress-induced malignant hyperthermia (MH) events are syndromes that primarily afflict military recruits in basic training and athletes. Events similar to those occurring in ER and in stress-induced MH events are triggered after exposure to anesthetic agents in MH-susceptible (MHS) patients. MH is an autosomal dominant hypermetabolic condition that occurs in genetically predisposed subjects during general anesthesia, induced by commonly used volatile anesthetics and/or the neuromuscular blocking agent succinylcholine. Triggering agents cause an altered intracellular calcium regulation. Mutations in RYR1 gene have been found in about 70% of MH families. The RYR1 gene encodes the skeletal muscle calcium release channel of the sarcoplasmic reticulum, commonly known as ryanodine receptor type 1 (RYR1). The present work reviews the documented cases of ER or of stress-induced MH events in which RYR1 sequence variations, associated or possibly associated to MHS status, have been identified. Antonella Carsana Copyright © 2013 Antonella Carsana. All rights reserved. Exercise-Induced Muscle Damage and Running Economy in Humans Mon, 04 Feb 2013 15:11:51 +0000 Running economy (RE), defined as the energy demand for a given velocity of submaximal running, has been identified as a critical factor of overall distance running performance. Plyometric and resistance trainings, performed during a relatively short period of time (~15–30 days), have been successfully used to improve RE in trained athletes. However, these exercise types, particularly when they are unaccustomed activities for the individuals, may cause delayed onset muscle soreness, swelling, and reduced muscle strength. Some studies have demonstrated that exercise-induced muscle damage has a negative impact on endurance running performance. Specifically, the muscular damage induced by an acute bout of downhill running has been shown to reduce RE during subsequent moderate and high-intensity exercise (>65% VO2max). However, strength exercise (i.e., jumps, isoinertial and isokinetic eccentric exercises) seems to impair RE only for subsequent high-intensity exercise (~90% VO2max). Finally, a single session of resistance exercise or downhill running (i.e., repeated bout effect) attenuates changes in indirect markers of muscle damage and blunts changes in RE. Cláudio de Oliveira Assumpção, Leonardo Coelho Rabello Lima, Felipe Bruno Dias Oliveira, Camila Coelho Greco, and Benedito Sérgio Denadai Copyright © 2013 Cláudio de Oliveira Assumpção et al. All rights reserved. Mitochondria as a Potential Regulator of Myogenesis Sun, 03 Feb 2013 08:10:32 +0000 Recent studies have shown that mitochondria play a role in the regulation of myogenesis. Indeed, the abundance, morphology, and functional properties of mitochondria become altered when the myoblasts differentiate into myotubes. For example, mitochondrial mass/volume, mtDNA copy number, and mitochondrial respiration are markedly increased after the onset of myogenic differentiation. Besides, mitochondrial enzyme activity is also increased, suggesting that the metabolic shift from glycolysis to oxidative phosphorylation as the major energy source occurs during myogenic differentiation. Several lines of evidence suggest that impairment of mitochondrial function and activity blocks myogenic differentiation. However, yet little is known about the molecular mechanisms underlying the regulation of myogenesis by mitochondria. Understanding how mitochondria are involved in myogenesis will provide a valuable insight into the underlying mechanisms that regulate the maintenance of cellular homeostasis. Here, we will summarize the current knowledge regarding the role of mitochondria as a potential regulator of myogenesis. Akira Wagatsuma and Kunihiro Sakuma Copyright © 2013 Akira Wagatsuma and Kunihiro Sakuma. All rights reserved. Muscle Wasting and Resistance of Muscle Anabolism: The “Anabolic Threshold Concept” for Adapted Nutritional Strategies during Sarcopenia Sun, 23 Dec 2012 17:24:47 +0000 Skeletal muscle loss is observed in several physiopathological situations. Strategies to prevent, slow down, or increase recovery of muscle have already been tested. Besides exercise, nutrition, and more particularly protein nutrition based on increased amino acid, leucine or the quality of protein intake has generated positive acute postprandial effect on muscle protein anabolism. However, on the long term, these nutritional strategies have often failed in improving muscle mass even if given for long periods of time in both humans and rodent models. Muscle mass loss situations have been often correlated to a resistance of muscle protein anabolism to food intake which may be explained by an increase of the anabolic threshold toward the stimulatory effect of amino acids. In this paper, we will emphasize how this anabolic resistance may affect the intensity and the duration of the muscle anabolic response at the postprandial state and how it may explain the negative results obtained on the long term in the prevention of muscle mass. Sarcopenia, the muscle mass loss observed during aging, has been chosen to illustrate this concept but it may be kept in mind that it could be extended to any other catabolic states or recovery situations. Dominique Dardevet, Didier Rémond, Marie-Agnès Peyron, Isabelle Papet, Isabelle Savary-Auzeloux, and Laurent Mosoni Copyright © 2012 Dominique Dardevet et al. All rights reserved. Maternal Aerobic Exercise during Pregnancy Can Increase Spatial Learning by Affecting Leptin Expression on Offspring's Early and Late Period in Life Depending on Gender Sun, 16 Sep 2012 16:07:51 +0000 Maternal exercise during pregnancy has been suggested to exert beneficial effects on brain functions of the offspring. Leptin is an adipocytokine which is secreted from adipose tissues and has positive effects on learning, memory, and synaptic plasticity. In this study, pregnant rats were moderately exercised and we observed the effects of this aerobic exercise on their prepubertal and adult offsprings' spatial learning, hippocampal neurogenesis, and expression of leptin. All the pups whose mothers exercised during pregnancy learned the platform earlier and spent longer time in the target quadrant. Their thigmotaxis times were shorter than those measured in the control group. It is shown that hippocampal CA1, CA3 neuron numbers increased in both prepubertal and adult pups, in addition that GD neuron numbers increased in adult pups. Leptin receptor expression significantly increased in the prepubertal male, adult male, and adult female pups. In our study, maternal running during pregnancy resulted in significant increase in the expression of leptin receptor but not in prepubertal female pups, enhanced hippocampal cell survival, and improved learning memory capability in prepubertal and adult rat pups, as compared to the control group. In conclusion, maternal exercise during pregnancy may regulate spatial plasticity in the hippocampus of the offspring by increasing the expression of leptin. Ayfer Dayi, Sinem Agilkaya, Seda Ozbal, Ferihan Cetin, Ilkay Aksu, Celal Gencoglu, Sultan Cingoz, Cetın Pekcetin, Kazim Tugyan, Berkant Muammer Kayatekin, and Nazan Uysal Copyright © 2012 Ayfer Dayi et al. All rights reserved. The Impact of Root Temperature on Photosynthesis and Isoprene Emission in Three Different Plant Species Mon, 04 Jun 2012 15:33:51 +0000 Most of the perennial plant species, particularly trees, emit volatile organic compounds (BVOCs) such as isoprene and monoterpenes, which in several cases have been demonstrated to protect against thermal shock and more generally against oxidative stress. In this paper, we show the response of three strong isoprene emitter species, namely, Phragmites australis, Populus x euramericana, and Salix phylicifolia exposed to artificial or natural warming of the root system in different conditions. This aspect has not been investigated so far while it is well known that warming the air around a plant stimulates considerably isoprene emission, as also shown in this paper. In the green house experiments where the warming corresponded with high stress conditions, as confirmed by higher activities of the main antioxidant enzymes, we found that isoprene uncoupled from photosynthesis at a certain stage of the warming treatment and that even when photosynthesis approached to zero isoprene emission was still ongoing. In the field experiment, in a typical cold-limited environment, warming did not affect isoprene emission whereas it increased significantly CO2 assimilation. Our findings suggest that the increase of isoprene could be a good marker of heat stress, whereas the decrease of isoprene a good marker of accelerated foliar senescence, two hypotheses that should be better investigated in the future. Mauro Medori, Lucia Michelini, Isabel Nogues, Francesco Loreto, and Carlo Calfapietra Copyright © 2012 Mauro Medori et al. All rights reserved. Renewed Avenues through Exercise Muscle Contractility and Inflammatory Status Thu, 03 May 2012 08:43:55 +0000 Physical inactivity leads to the accumulation of visceral fat and, consequently, to the activation of a network of inflammatory pathways which may promote development of insulin resistance, atherosclerosis, neurodegeneration, and tumour growth. These conditions belong to the “diseasome of physical inactivity”. In contrast, the protective effect of regular exercise against diseases associated with chronic inflammation may to some extent be ascribed to an anti-inflammatory effect. The so called “acute exercise threshold”, the complex mixture of several variables involved in exercise, such as type, volume, frequency, and intensity range is capable of inducing positive physiological adaptations and has been specifically addressed in the recent literature. The major concern is related to the level of the threshold: “exercise training shifts from a therapeutic adaptive intervention to one with potential pathological consequences”. Nonetheless, if the mechanical stimulus is too weak to disrupt cellular homeostasis, training adaptations will not occur. Answering these questions could present practical applications, especially during inflammatory diseases associated with detrimental muscle effects and could theoretically constitute a “new” therapeutic approach to treat/improve an inflammatory state. This paper aims to describe specific data from the literature regarding the effects of exercise on inflammatory diseases in order to promote a more sophisticated perspective on the anti-inflammatory effects of exercise. Nelo Eidy Zanchi, Felipe Natali Almeida, Fábio Santos Lira, José César Rosa Neto, Humberto Nicastro, Claudia Ribeiro da Luz, Mário Alves de Siqueira Filho, Vitor Felitti, Mariz Vainzof, Marilia Seelaender, Jacques R. Poortmans, and Antonio Herbert Lancha Jr. Copyright © 2012 Nelo Eidy Zanchi et al. All rights reserved. Strength Training with Superimposed Whole Body Vibration Does Not Preferentially Modulate Cortical Plasticity Wed, 02 May 2012 16:08:47 +0000 Paired-pulse transcranial magnetic stimulation (TMS) was used to investigate 4 wks of leg strength training with and without whole body vibration (WBV) on corticospinal excitability and short-latency intracortical inhibition (SICI). Participants (𝑛=12) were randomly allocated to either a control or experimental (WBV) group. All participants completed 12 squat training sessions either with (WBV group) or without (control group) exposure to WBV (𝑓=35 Hz, 𝐴=2.5 mm). There were significant (𝑃<0.05) increases in squat strength and corticospinal excitability and significant (𝑃<0.05) reductions in SICI for both groups following the 4 wk intervention. There were no differences detected between groups for any dependant variable (𝑃>0.05). It appears that WBV training does not augment the increase in strength or corticospinal excitability induced by strength training alone. Ashleigh T. Weier and Dawson J. Kidgell Copyright © 2012 Ashleigh T. Weier and Dawson J. Kidgell. All rights reserved. Aerobic Fitness Evaluation during Walking Tests Identifies the Maximal Lactate Steady State Tue, 01 May 2012 16:06:52 +0000 Objective. The aim of this study was to verify the possibility of lactate minimum (LM) determination during a walking test and the validity of such LM protocol on predicting the maximal lactate steady-state (MLSS) intensity. Design. Eleven healthy subjects (24.2±4.5 yr; 74.3±7.7 kg; 176.9±4.1 cm) performed LM tests on a treadmill, consisting of walking at 5.5 km⋅h−1 and with 20–22% of inclination until voluntary exhaustion to induce metabolic acidosis. After 7 minutes of recovery the participants performed an incremental test starting at 7% incline with increments of 2% at each 3 minutes until exhaustion. A polynomial modeling approach (LMp) and a visual inspection (LMv) were used to identify the LM as the exercise intensity associated to the lowest [bLac] during the test. Participants also underwent to 2–4 constant intensity tests of 30 minutes to determine the MLSS intensity. Results. There were no differences among LMv (12.6±1.7%), LMp (13.1±1.5%), and MLSS (13.6±2.1%) and the Bland and Altman plots evidenced acceptable agreement between them. Conclusion. It was possible to identify the LM during walking tests with intensity imposed by treadmill inclination, and it seemed to be valid on identifying the exercise intensity associated to the MLSS. Guilherme Morais Puga, Eduardo Kokubun, Herbert Gustavo Simões, Fabio Yuzo Nakamura, and Carmen Sílvia Grubert Campbell Copyright © 2012 Guilherme Morais Puga et al. All rights reserved. Changes in Cardiac Tone Regulation with Fatigue after Supra-Maximal Running Exercise Mon, 30 Apr 2012 13:53:10 +0000 To investigate the effects of fatigue and metabolite accumulation on the postexercicse parasympathetic reactivation, 11 long-sprint runners performed on an outdoor track an exhaustive 400 m long sprint event and a 300 m with the same 400 m pacing strategy. Time constant of heart rate recovery (HRR𝜏), time (RMSSD), and frequency (HF, and LF) varying vagal-related heart rate variability indexes were assessed during the 7 min period immediately following exercise. Biochemical parameters (blood lactate, pH, PO2, PCO2, SaO2, and HCO3−) were measured at 1, 4 and 7 min after exercise. Time to perform 300 m was not significantly different between both running trials. HHR𝜏 measured after the 400 m running exercise was longer compared to 300 m running bouts (183.7±11.6 versus 132.1±9.8 s, 𝑃<0.01). Absolute power density in the LF and HF bands was also lower after 400 m compared to the 300 m trial (𝑃<0.05). No correlation was found between biochemical and cardiac recovery responses except for the PO2 values which were significantly correlated with HF levels measured 4 min after both bouts. Thus, it appears that fatigue rather than metabolic stresses occurring during a supramaximal exercise could explain the delayed postexercise parasympathetic reactivation in longer sprint runs. Pierre-Marie Leprêtre, Philippe Lopes, Claire Thomas, and Christine Hanon Copyright © 2012 Pierre-Marie Leprêtre et al. All rights reserved. Effects of Exercise on Oxidative Stress in Rats Induced by Ozone Tue, 24 Apr 2012 13:21:48 +0000 Oxidative stress (OS) induced by acute exercise is reduced by chronic exercise. Ozone (O3) exposure produces OS. The aim of this study was to determine if aerobic exercise (AE) reduced OS produced by O3. A pilot experiment was performed with male Wistar rats submitted to AE (trained to swim 90 min/day). Adaptation to exercise was demonstrated three weeks after training by means of changes in reduced nitrates (NOx) in plasma. Therefore, two-week training was chosen for the following experiments. Six of twelve trained rats were exposed to O3 (0.5 ppm, 4 h/day, one hour before exercise). Two groups of sedentary animals (𝑛=6 each) were used as controls, one of which was exposed to O3. At the end of the experiments NOx, 8-isoprostane (8-IP), malondialdehyde (MDA), superoxide dismutase (SOD) activity, and carbonyls (CBs) were measured in plasma. CBs did not change in any group. O3-induced OS was manifested by reduced NOx and SOD activity, as well as increased 8-IP and MDA. Exercise significantly blocked O3 effects although SOD was also decreased by exercise (a greater drop occurring in the O3 group). It is concluded that AE protects against OS produced by O3 and the effect is independent of SOD. Catalina Martinez-Campos, Eleazar Lara-Padilla, Rosa Amalia Bobadilla-Lugo, Robert David Kross, and Cleva Villanueva Copyright © 2012 Catalina Martinez-Campos et al. All rights reserved. Glucose and Fat Oxidation: Bomb Calorimeter Be Damned Thu, 19 Apr 2012 16:05:05 +0000 For both respiration and combustion, the energy loss difference between glucose and fat oxidation often is referenced to the efficiency of the fuel. Yet, the addition of anaerobic metabolism with ATP resynthesis to complete respiratory glucose oxidation further contributes to energy loss in the form of entropy changes that are not measured or quantified by calorimetry; combustion and respiratory fat/lactate oxidation lack this anaerobic component. Indeed, the presence or absence of an anaerobic energy expenditure component needs to be applied to the estimation of energy costs in regard to glucose, lactate, and fuel oxidation, especially when the measurement of oxygen uptake alone may incorrectly define energy expenditure. Christopher B. Scott Copyright © 2012 Christopher B. Scott. All rights reserved. Intracellular Shuttle: The Lactate Aerobic Metabolism Thu, 19 Apr 2012 13:45:36 +0000 Lactate is a highly dynamic metabolite that can be used as a fuel by several cells of the human body, particularly during physical exercise. Traditionally, it has been believed that the first step of lactate oxidation occurs in cytosol; however, this idea was recently challenged. A new hypothesis has been presented based on the fact that lactate-to-pyruvate conversion cannot occur in cytosol, because the LDH enzyme characteristics and cytosolic environment do not allow the reaction in this way. Instead, the Intracellular Lactate Shuttle hypothesis states that lactate first enters in mitochondria and only then is metabolized. In several tissues of the human body this idea is well accepted but is quite resistant in skeletal muscle. In this paper, we will present not only the studies which are protagonists in this discussion, but the potential mechanism by which this oxidation occurs and also a link between lactate and mitochondrial proliferation. This new perspective brings some implications and comes to change our understanding of the interaction between the energy systems, because the product of one serves as a substrate for the other. Rogério Santos de Oliveira Cruz, Rafael Alves de Aguiar, Tiago Turnes, Rafael Penteado Dos Santos, Mariana Fernandes Mendes de Oliveira, and Fabrizio Caputo Copyright © 2012 Rogério Santos de Oliveira Cruz et al. All rights reserved. Supercooling Agent Icilin Blocks a Warmth-Sensing Ion Channel TRPV3 Sun, 01 Apr 2012 11:41:02 +0000 Transient receptor potential vanilloid subtype 3 (TRPV3) is a thermosensitive ion channel expressed in a variety of neural cells and in keratinocytes. It is activated by warmth (33–39°C), and its responsiveness is dramatically increased at nociceptive temperatures greater than 40°C. Monoterpenoids and 2-APB are chemical activators of TRPV3 channels. We found that Icilin, a known cooling substance and putative ligand of TRPM8, reversibly inhibits TRPV3 activity at nanomolar concentrations in expression systems like Xenopus laeves oocytes, HEK-293 cells, and in cultured human keratinocytes. Our data show that icilin's antagonistic effects for the warm-sensitive TRPV3 ion channel occurs at very low concentrations. Therefore, the cooling effect evoked by icilin may at least in part be due to TRPV3 inhibition in addition to TRPM8 potentiation. Blockade of TRPV3 activity by icilin at such low concentrations might have important implications for overall cooling sensations detected by keratinocytes and free nerve endings in skin. We hypothesize that blockage of TRPV3 might be a signal for cool-sensing systems (like TRPM8) to beat up the basal activity resulting in increased cold perception when warmth sensors (like TRPV3) are shut off. Muhammad Azhar Sherkheli, Guenter Gisselmann, and Hanns Hatt Copyright © 2012 Muhammad Azhar Sherkheli et al. All rights reserved. Lymphocytes Mitochondrial Physiology as Biomarker of Energy Metabolism during Fasted and Fed Conditions Mon, 12 Mar 2012 14:28:12 +0000 Mitochondria are central coordinators of energy metabolism, and changes of their physiology have long been associated with metabolic disorders. Thus, observations of energy dynamics in different cell types are of utmost importance. Therefore, tools with quick and easy handling are needed for consistent evaluations of such interventions. In this paper, our main hypothesis is that during different nutritional situations lymphocytes mitochondrial physiology could be associated with the metabolism of other cell types, such as cardiomyocytes, and consequently be used as metabolic biomarker. Blood lymphocytes and heart muscle fibers were obtained from both fed and 24 h-fasted mice, and mitochondrial analysis was assessed by high-resolution respirometry and western blotting. Carbohydrate-linked oxidation and fatty acid oxidation were significantly higher after fasting. Carnitine palmitoil transferase 1 and uncouple protein 2 contents were increased in the fasted group, while the glucose transporters 1 and 4 and the ratio phosphorylated AMP-activated protein kinase/AMPK did not change between groups. In summary, under a nutritional status modification, mitochondria demonstrated earlier adaptive capacity than other metabolic sensors such as glucose transporters and AMPK, suggesting the accuracy of mitochondria physiology of lymphocytes as biomarker for metabolic changes. Erika Cortez, Fabiana A. Neves, Amélia F. Bernardo, Ana Carolina Stumbo, Laís Carvalho, Érica Garcia-Souza, Rosely Sichieri, and Anibal S. Moura Copyright © 2012 Erika Cortez et al. All rights reserved. Changes in Hemodynamics and Tissue Oxygenation Saturation in the Brain and Skeletal Muscle Induced by Speech Therapy – A Near-Infrared Spectroscopy Study Mon, 01 Jan 1900 00:00:00 +0000 Arts speech therapy (AST) is a therapeutic method within complementary medicine and has been practiced for decades for various medical conditions. It comprises listening and the recitation of different forms of speech exercises under the guidance of a licensed speech therapist. The aim of our study was to noninvasively investigate whether different types of recitation influence hemodynamics and oxygenation in the brain and skeletal leg muscle using near-infrared spectroscopy (NIRS). Seventeen healthy volunteers (eight men and nine women, mean age ± standard deviation 35.6 ± 12.7 years) were enrolled in the study. Each subject was measured three times on different days with the different types of recitation: hexameter, alliteration, and prose verse. Before, during, and after recitation, relative concentration changes of oxyhemoglobin (Δ[O2Hb]), deoxyhemoglobin (Δ[HHb]), total hemoglobin (Δ[tHb]), and tissue oxygenation saturation (StO2) were measured in the brain and skeletal leg muscle using a NIRS device. The study was performed with a randomized crossover design. Significant concentration changes were found during recitation of all verses, with mainly a decrease in Δ[O2Hb] and ΔStO2 in the brain, and an increase in Δ[O2Hb] and Δ[tHb] in the leg muscle during recitation. After the recitations, significant changes were mainly increases of Δ[HHb] and Δ[tHb] in the calf muscle. The Mayer wave spectral power (MWP) was also significantly affected, i.e., mainly the MWP of the Δ[O2Hb] and Δ[tHb] increased in the brain during recitation of hexameter and prose verse. The changes in MWP were also significantly different between hexameter and alliteration, and hexameter and prose. Possible physiological explanations for these changes are discussed. A probable reason is a different effect of recitations on the sympathetic nervous system. In conclusion, these changes show that AST has relevant effects on the hemodynamics and oxygenation of the brain and muscle. U. Wolf, F. Scholkmann, R. Rosenberger, M. Wolf, and M. Nelle Copyright © 2011 Ursula Wolf et al. All rights reserved. Uric Acid or 1-Methyl Uric Acid in the Urinary Bladder Increases Serum Glucose, Insulin, True Triglyceride, and Total Cholesterol Levels in Wistar Rats Mon, 01 Jan 1900 00:00:00 +0000 In animals deprived of food for a long period, a drop in the fat mass below 5% of the total body mass results in an increase in blood glucocorticoids and uric acid levels, followed by foraging activity. Since the glucocorticoids increase the uric acid excretion, an increase in the level of uric acid in the bladder urine could be the signal for this feeding behaviour and subsequent fat storage. Accumulation of fat is associated with hyperglycaemia, hyperinsulinaemia, hyperlipidaemia, and hypercholesterolaemia as seen in the metabolic syndrome or hibernation. It is hypothesized that uric acid or its structurally related compound, 1-methyl uric acid (one of the metabolites of the methyl xanthines namely caffeine, theophylline, and theobromine present in coffee, tea, cocoa, and some drugs), can act on the urinary bladder mucosa and increases the blood glucose, insulin, triglyceride, and cholesterol levels. In rats, perfusion of the urinary bladder with saturated aqueous solution of uric acid or 1-methyl uric acid results in a significant increase in the serum levels of glucose, insulin, true triglyceride, and total cholesterol in comparison with perfusion of the bladder with distilled water at 20, 40, and 80 min. The uric acid or the 1-methyl uric acid acts on the urinary bladder mucosa and increases the serum glucose, insulin, true triglyceride, and total cholesterol levels. T. Balasubramanian Copyright © 2003 T. Balasubramanian. All rights reserved. Honey for Wound Healing, Ulcers, and Burns; Data Supporting Its Use in Clinical Practice Mon, 01 Jan 1900 00:00:00 +0000 The widespread existence of unhealed wounds, ulcers, and burns has a great impact on public health and economy. Many interventions, including new medications and technologies, are being used to help achieve significant wound healing and to eliminate infections. Therefore, to find an intervention that has both therapeutic effect on the healing process and the ability to kill microbes is of great value. Honey is a natural product that has been recently introduced in modern medical practice. Honey's antibacterial properties and its effects on wound healing have been thoroughly investigated. Laboratory studies and clinical trials have shown that honey is an effective broad-spectrum antibacterial agent. This paper reviews data that support the effectiveness of natural honey in wound healing and its ability to sterilize infected wounds. Studies on the therapeutic effects of honey collected in different geographical areas on skin wounds, skin and gastric ulcers, and burns are reviewed and mechanisms of action are discussed. (Ulcers and burns are included as an example of challenging wounds.) The data show that the wound healing properties of honey include stimulation of tissue growth, enhanced epithelialization, and minimized scar formation. These effects are ascribed to honey's acidity, hydrogen peroxide content, osmotic effect, nutritional and antioxidant contents, stimulation of immunity, and to unidentified compounds. Prostaglandins and nitric oxide play a major role in inflammation, microbial killing, and the healing process. Honey was found to lower prostaglandin levels and elevate nitric oxide end products. These properties might help to explain some biological and therapeutic properties of honey, particularly as an antibacterial agent or wound healer. The data presented here demonstrate that honeys from different geographical areas have considerable therapeutic effects on chronic wounds, ulcers, and burns. The results encourage the use of honey in clinical practice as a natural and safe wound healer. Noori Al-Waili, Khelod Salom, and Ahmad A. Al-Ghamdi Copyright © 2011 Noori Al-Waili et al. All rights reserved. Signaling Pathway Puts the Break on Fat Cell Formation Mon, 01 Jan 1900 00:00:00 +0000 Obesity is approaching epidemic proportions in the western industrialized world, and is also becoming a major problem among young people in eastern and developing countries [1,2,3]. Unfortunately, excess fat or adipose tissue is associated with a wide array of health problems, including increased incidence of type II diabetes, cardiovascular disease, hypertension, sleep apnea, and skeletomuscular problems [4,5,6]. Obesity is the second leading cause of death from “unnecessary” causes in the U.S. (after smoking), and costs individuals and society billions of dollars worldwide to treat. Despite common wisdom that “one just needs to eat less and exercise more” and a multi-billion-dollar diet industry, epidemiological data indicate that the incidence of obesity will continue to rise. This alarming trend is, in part, due to the unprecedented availability of energy-dense foods and an increasingly sedentary lifestyle. These environmental factors may be complicated in some individuals by an unfavorable genetic predisposition. Pharmaceutical companies lead active research programs to identify drugs that target weight control centers in the body and which may help individuals control their weight; however, no satisfactory magic bullet to fight obesity has yet come through the pipeline [7,8]. Ormond A. MacDougald Copyright © 2001 Ormond A. MacDougald. All rights reserved. Interlimb Transfer of Grasp Orientation is Asymmetrical Mon, 01 Jan 1900 00:00:00 +0000 One the most fundamental aspects of the human motor system is the hemispheric asymmetry seen in behavioral specialization. Hemispheric dominance can be inferred by a contralateral hand preference in grasping. Few studies have considered grasp orientation in the context of manual lateralization and none has looked at grasp orientation with natural prehension. Thirty right-handed adults performed precision grasps of a cylinder using the thumb and index fingers, and the opposition axis (OA) was defined as the line connecting these two contact points on the cylinder. Subjects made ten consecutive grasps with one hand (primary hand movements) followed by ten grasps with the other hand (trailing movements). Differences between primary and trailing grasps revealed that each hemisphere is capable of programming the orientation of the OA and that primary movements with the right hand significantly influenced OA orientation of the trailing left hand. These results extend the hemispheric dominance of the left hemisphere to the final positions of fingers during prehension. Victor Frak, D. Bourbonnais, I. Croteau, and H. Cohen Copyright © 2006 Victor Frak et al. All rights reserved. Effects of Changes in Colored Light on Brain and Calf Muscle Blood Concentration and Oxygenation Mon, 01 Jan 1900 00:00:00 +0000 Color light therapy is a therapeutic method in complementary medicine. In color therapy, light of two contrasting colors is often applied in a sequential order. The aim of this study was to investigate possible physiological effects, i.e., changes in the blood volume and oxygenation in the brain and calf muscle of healthy subjects who were exposed to red and blue light in sequential order. The hypothesis was that if a subject is first exposed to blue and then red light, the effect of the red light will be enhanced due to the contrastingly different characteristics of the two colors. The same was expected for blue light, if first exposing a subject to red and then to blue light. Twelve healthy volunteers (six male, six female) were measured twice on two different days by near-infrared spectroscopy during exposure to colored light. Two sequences of colored light were applied in a controlled, randomized, crossover design: first blue, then red, and vice versa. For the brain and muscle, the results showed no significant differences in blood volume and oxygenation between the two sequences, and a high interindividual physiological variability. Thus, the hypothesis had to be rejected. Comparing these data to results from a previous study, where subjects were exposed to blue and red light without sequential color changes, shows that the results of the current study appear to be similar to those of red light exposure. This may indicate that the exposure to red light was preponderant and thus effects of blue light were outweighed. J. Weinzirl, M. Wolf, P. Heusser, M. Nelle, and U. Wolf Copyright © 2011 Johannes Weinzirl et al. All rights reserved. Back from the Tip of the Nose Mon, 01 Jan 1900 00:00:00 +0000 About 130 years ago, Giulio Bizozzero, then in Pavia, made a seminal observation [1]. He divided the tissues of the vertebrate body into three categories: those that divide constantly (labile), such as blood and skin, those that never divide, such as striated muscle and brain (perennial), and those that normally do not divide but can do so if injured (stable). As a consequence, diseases that perturb cell division, such as cancer, affect labile tissues, while degenerative diseases affect perennial tissues where repair is inefficient. Epithelia and blood possess a reservoir of cells that divide and maintain a progenitor pool throughout life (the stem cells) whereas striated muscle and brain were supposed not to contain stem cells. Furthermore, stem cells were supposed to generate only the cells of the tissue where they belong. Giulio Cossu Copyright © 2001 Giulio�Cossu. All rights reserved. Finding the Stuff that Dreams are Made Of Mon, 01 Jan 1900 00:00:00 +0000 The scientific study of dreams has had a long but tortured history. While the discovery of REM sleep in 1953 [1] and its strong correlation with dreaming [2] led to a renewed hope that the study of dreaming could be moved to a solidly scientific and physiological base, such studies have provided only mixed success. In 1977, Hobson and McCarley [3] proposed the activation-synthesis model for dream construction based on the physiological features of REM sleep, but since then the field has shown surprisingly little progress. Robert Stickgold Copyright © 2001 Robert Stickgold. All rights reserved. Handgrip Strength as a Diagnostic Tool in Work-Related Upper Extremity Musculoskeletal Disorders in Women Mon, 01 Jan 1900 00:00:00 +0000 The aim of this study was to determine if handgrip strength might be used as a diagnostic tool in musculoskeletal disorders of the upper extremities in women working in an industrial environment. The setting was an electronic factory with four groups of women (n = 101) in a factory assembling electronic components. Handgrip strength was measured using a Jamar® hydraulic hand dynamometer. The study investigated grip strength in managers-engineers, cable wiring, circuit board assembly, integrated circuits women at 90? elbow flexion and 180? elbow extension. Women seeking or receiving medical care for musculoskeletal disorders of the upper extremities or neck showed significant declines (p < 0.01) in handgrip strength and these also related to the type of work and the level of perceived physical exertion. Women in the managerial-engineering group showed fewer musculoskeletal disorders of the upper extremity compared with the other groups and also had significantly stronger handgrip. Our findings encourage us to recommend hand dynamometer testing as a useful diagnostic tool to determine loss of handgrip strength. Deborah Alperovitch-Najenson, Eli Carmeli, Raymond Coleman, and Haim Ring Copyright © 2004 Deborah Alperovitch-Najenson et al. All rights reserved. The Insulin-Sensitive Side of SHIP2 Mon, 01 Jan 1900 00:00:00 +0000 A substantial and increasing proportion of death and disability in the EU (and elsewhere) is attributable to diseases associated with insulin resistance (i.e., decreased insulin sensitivity). Beside type II diabetes, other diseases like obesity, hypertension, atherosclerosis, hyperlipidaemia, polycystic ovarian syndrome, and acromegaly are indeed associated with insulin resistance [1]. Stephane Schurmans Copyright © 2001 Stephane Schurmans. All rights reserved.