Physiology Journal http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Quantitative Analysis of the Relationship between Blood Vessel Wall Constituents and Viscoelastic Properties: Dynamic Biomechanical and Structural In Vitro Studies in Aorta and Carotid Arteries Wed, 09 Apr 2014 12:02:41 +0000 http://www.hindawi.com/journals/physiology/2014/142421/ The purposes of this work were to perform in sheep a quantification of the elastic, viscous, and inertial moduli obtained in carotid and aortic artery segments during in vitro dynamic studies that mimic the normal circulatory function; a quantitative determination of collagen, elastin, and vascular smooth muscle of the carotid and aortic segments analyzed in vitro; the correlation between the amounts of each arterial wall constituent and the viscoelastic properties. To this end, nine healthy sheep were included. One artery was selected from each animal to evaluate its biomechanical properties: (a) in three sheep the ascending aorta, (b) in three the thoracic descending aorta, and (c) in the remaining three the proximal segments of the carotid artery. Each selected artery was instrumented with pressure and diameter sensors. After excision, a small ring-shaped sample was set apart from each segment for histological analysis. In conclusion, (a) the arterial compliance showed a positive association with the absolute and relative amount of the parietal elastin, and (b) arterial viscosity was positively associated with the relative amount of smooth muscle, and this association was increased when the correlation was calculated considering the amount of collagen as well as the amount of smooth muscle. Daniel Bia, Yanina Zócalo, Edmundo I. Cabrera-Fischer, Sandra Wray, and Ricardo L. Armentano Copyright © 2014 Daniel Bia et al. All rights reserved. Mitigating the Effects of Salinity by Foliar Application of Salicylic Acid in Fenugreek Tue, 01 Apr 2014 09:05:58 +0000 http://www.hindawi.com/journals/physiology/2014/869058/ Present research work was conducted to alleviate the salinity-induced harmful effect on biomass production and physiochemical attributes of fenugreek by foliar application of salicylic acid. Two varieties (Deli Kabul and Kasuri) were grown in salt treated (100 mM NaCl) and untreated (0 mM NaCl) growth medium. Two levels of salicylic acid (0 mg L−1 and 100 mg L−1) were applied through foliar method. Salinity stress significantly reduced the growth biomass in both varieties. Higher shoot fresh weight was recorded in Deli Kabul, while lower in Kasuri. Such reduction in growth biomass was mitigated by the foliar application of SA in both plants. Salinity caused a marked reduction in gas exchange attributes including net CO2 assimilation rate, transpiration rate, stomatal conductance, and substomatal CO2 concentration. Exogenous applied salicylic acid also overcomes the reduction in gas exchange attributes of the plants. The varieties “Deli Kabul” and “Kasuri” showed higher and lower net CO2 assimilation rate, respectively. These results indicate that growth medium salinity induced reduction in biomass production, gas exchange attributes, and also chlorophyll contents whereas the application of SA through foliar method can be used to protect plant growth and improve these attributes under salt stress. Sumaira Babar, Ejaz Hussain Siddiqi, Iqbal Hussain, Khizar Hayat Bhatti, and Rizwan Rasheed Copyright © 2014 Sumaira Babar et al. All rights reserved. Comparison of the Effects of Glucose and Fructose on Exercise Metabolism, Perceived Exertion, and Recovery in Untrained Females Wed, 19 Feb 2014 00:00:00 +0000 http://www.hindawi.com/journals/physiology/2014/383092/ This double-blinded, crossover randomized controlled trial study was designed to establish if combined ingestion of glucose and fructose (GLU + FRU) at the moderate rate 0.5 g·min−1 would result in higher rates of carbohydrate (CHO) oxidation compared with glucose (GLU) alone. Eight untrained females (VO2max: 25.8 ± 3.2 mL·kg−1·min−1) cycled on two different occasions for 60 min at 50% of maximal power output (60% ± 1 % VO2max) and consumed 12% CHO solution of either providing 0.33 g·min−1 glucose + 0.17 g·min−1 fructose (GLU + FRUC) or 0.5 g·min−1 of glucose (GLU) alone. Heart rate (HR) and rate of perceived exertion (RPE) were assessed during exercise and subjective exercise experience assessed two days after each trial. CHO oxidation was not significantly different () between GLU + FRU and GLU (0.8 ± 0.06 g·min−1 and 0.78 ± 0.05 g·min−1, resp.). CHO oxidation rates during the final 30 min of the recovery period were not significantly different between GLU + FRU and GLU (0.17 ± 0.04 g·min−1 and 0.14 ± 0.05 g·min−1, resp.). Experience of distress was significantly higher () for GLU compared to GLU + FRU. The results reveal that consuming modest amounts of glucose plus fructose does not boost CHO oxidation above that of glucose alone during submaximal exercise. Babatunde O. Folarin, Ian A. Macdonald, Latif Khaled, Patterson Jill, Capocci Hannah, Thirkell Phil, and Macdermid C. Joy Copyright © 2014 Babatunde O. Folarin et al. All rights reserved. Sex Differences in Peripheral Augmentation Index and Arterial Reservoir Pressure during Upper Limb Postural Shifts Sun, 05 Jan 2014 13:54:27 +0000 http://www.hindawi.com/journals/physiology/2014/971906/ We examined the peripheral hemodynamic response to passive arm postural changes in young men and women. Radial artery pulse waveforms were captured using applanation tonometry in 20 men (age 27 ± 2 yrs, BMI 25 ± 1 kg/m2) and 20 women (age 27 ± 2 yrs, BMI 23±1 kg/m2). Arm position was maintained at either heart level or supported 14 cm above/below heart level in a randomized fashion. Systolic augmentation index (sAIx) and diastolic augmentation index (dAIx) were used as estimates of pressure from wave reflections arriving in systole and diastole, respectively. A novel reservoir-wave separation technique was used to obtain arterial reservoir pressure (pressure generated by arterial capacitance). Women showed a significant reduction in radial diastolic pressure-time integral (DPTI) () and reservoir pressure (), with no change in peripheral sAIx () or dAIx () when moving the arm from below to above heart level. Conversely, men showed an attenuated change in radial DPTI () concomitant with significant increases in reservoir pressure (), sAIx (), and dAIx (). Gravity-mediated changes in regional hemodynamics produced by passive arm postural shifts are sex specific. Men demonstrate less change in regional diastolic pressure concomitant with increased augmentation index and arterial reservoir pressure. Kevin S. Heffernan, Ari G. Kasprowicz, Brendan J. Tarzia, Justin E. Davies, and Darren P. Casey Copyright © 2014 Kevin S. Heffernan et al. All rights reserved. Changes in Haematological Indices in Normal Pregnancy Mon, 30 Dec 2013 14:10:13 +0000 http://www.hindawi.com/journals/physiology/2013/283814/ Variation in some haematological indices during normal pregnancy was investigated. The test group comprised 200 pregnant women who presented themselves at the Capitol Hill Clinic Warri, Delta State, Nigeria, for antenatal care while the control group comprised 80 nonpregnant women randomly selected from the student population in Delta State University, Abraka. Data generated from the pretest questionnaire indicated that 55.8% of the research participants experienced an increase in appetite. The analysis of haematological indices was done using automated hematological analyzer. The result from the study showed that there was a significant decrease () in the PCV of the test group ()% when compared to the control ()%. Similarly, the result of the blood haemoglobin showed a significant difference () between the test () g/dL and the control group () g/dL while granulocytes and platelets also showed significant decrease () with lymphocytes increasing significantly; the total white blood cell count (WBC) showed no significant difference; there was an increased level compared to the control. The study concluded that pregnancy in women has the tendency to alter haematological indices. Patrick Chukwuyenum Ichipi-Ifukor, Juliet Jacobs, Rita Ngozi Ichipi-Ifukor, and Oberhiri Lawrence Ewrhe Copyright © 2013 Patrick Chukwuyenum Ichipi-Ifukor et al. All rights reserved. Combined Effects of Stretching and Resistance Training on Ankle Joint Flexibility Wed, 18 Dec 2013 16:16:46 +0000 http://www.hindawi.com/journals/physiology/2013/171809/ The purpose of the present study was to clarify the combined effects of stretching and resistance training on the active and passive dorsiflexion range of motion of ankle joint. Sixteen young adult men were randomly assigned to a training () or a control () group. The training group trained one leg for the combined program of static calf stretching and dorsiflexors resistance training program (STR+TR) and the other leg for static stretching program only (STR). The training group executed stretching of both legs every day and resistance training every other day for six weeks. After the training program, in STR+TR side, both active and passive dorsiflexion range of motions significantly () increased and also isometric maximal voluntary dorsiflexion torque increased, while in STR side, only passive dorsiflexion range of motion increased. In passive dorsiflexion range of motion, increased dorsiflexion ROM was accompanied by increased tendon elongation not muscle elongation. In conclusion, the combined program of stretching for calf muscles and resistance training for dorsiflexors increases active as well as passive dorsiflexion range of motion, while static calf stretching program is effective only for the increase in passive dorsiflexion range of motion. E. Kato, T. Kurihara, H. Kanehisa, T. Fukunaga, and Y. Kawakami Copyright © 2013 E. Kato et al. All rights reserved. Reliability of Calf Bioelectrical Impedance Spectroscopy and Magnetic-Resonance-Imaging-Acquired Skeletal Muscle Hydration Measures in Healthy People Mon, 02 Sep 2013 11:48:05 +0000 http://www.hindawi.com/journals/physiology/2013/563494/ Purpose. The purpose of this study was to investigate the test-retest reliability, relative variability, and agreement between calf bioelectrical impedance-spectroscopy (cBIS) acquired extracellular fluid (ECF), intracellular fluid (ICF), total water and the ratio of ECF : ICF, magnetic-resonance-imaging (MRI) acquired transverse relaxation times (), and apparent diffusion coefficient (ADC) of calf muscles of the same segment in healthy individuals. Methods. Muscle hydration measures were collected in 32 healthy individuals on two occasions and analyzed by a single rater. On both occasions, MRI measures were collected from tibialis anterior (TA), medial (MG), and lateral gastrocnemius (LG) and soleus muscles following the cBIS data acquired using XiTRON Hydra 4200 BIS device. The intraclass correlation coefficients (ICC2,1), coefficient of variation (CV), and agreement between MRI and cBIS data were also calculated. Results. ICC2,1 values for cBIS, , and ADC ranged from 0.56 to 0.92, 0.96 to 0.99, and 0.05 to 0.56, respectively. Relative variability between measures (CV) ranged from 14.6 to 25.6% for the cBIS data and 4.2 to 10.0% for the MRI-acquired data. The ratio of ECF : ICF could significantly predict of TA and soleus muscles. Conclusion. MRI-acquired measures of had the highest test-retest reliability of muscle hydration with the least error and variation on repeated testing. Hence, of a muscle is the most reliable and stable outcome measure for evaluating individual muscle hydration. Anuradha Sawant, Andrew A. House, Bert M. Chesworth, Joseph Gati, Robert Lindsay, Denise M. Connelly, Robert Bartha, and Tom J. Overend Copyright © 2013 Anuradha Sawant et al. All rights reserved. Altered Responses to Cold Environment in Urocortin 1 and Corticotropin-Releasing Factor Deficient Mice Mon, 27 May 2013 08:08:07 +0000 http://www.hindawi.com/journals/physiology/2013/185767/ We examined core body temperature (CBT) of urocortin 1 (UCN1) and corticotropin releasing factor (CRF) knockout (KO) mice exposed to 4°C for 2 h. UCN1KO mice showed higher average CBT during cold exposure as compared to WT. The CBT of male and female WT mice dropped significantly to and  C at 4°C, respectively. In contrast, the CBT of male and female UCN1KO mice dropped only slightly after 2 h at 4°C to and  C, respectively. WT female and male UCN1KO mice showed significant acclimatization to cold; however, female UCN1KO mice did not show such a significant acclimatization. CRFKO mice showed a dramatic decline in CBT from at 22°C to at 4°C for 2 h. The CRF/UCN1 double KO (dKO) mice dropped their CBT to after 2 h exposure to 4°C. Dexamethasone treatment prevented the decline in CBT of the CRFKO and the dKO mice. Taken together, the data suggest a novel role for UCN1 in thermoregulation. The role of CRF is likely secondary to adrenal glucocorticoids, which have an important regulatory role on carbohydrate, fat, and protein metabolism. Bayan Chaker, Tareq A. Samra, Nabanita S. Datta, and Abdul B. Abou-Samra Copyright © 2013 Bayan Chaker et al. All rights reserved. A Single Amino Acid Substitution in the Renal Betaine/GABA Transporter Prevents Trafficking to the Plasma Membrane Tue, 16 Apr 2013 18:28:07 +0000 http://www.hindawi.com/journals/physiology/2013/598321/ One response to hypertonic stress in the renal medulla and MDCK cells is the upregulation of betaine transporter (BGT1) synthesis, followed by trafficking to the plasma membrane (PM) and an increase in betaine transport. Upregulation of BGT1 was enhanced by inhibitors of phosphatases PP1 and PP2A and was attenuated by inhibitors of protein kinase C, suggesting an important role for phosphorylation reactions. This was tested using mutants of BGT1 tagged with EGFP. The PM trafficking motifs of BGT1 reside near the C terminus, and truncation at lysine560 resulted in a protein that remained intracellular during hypertonic stress. This K560 mutant colocalized with endoplasmic reticulum (ER). Substitution of alanine at Thr40, a putative phosphorylation site, also prevented trafficking to the PM during hypertonic stress. Live-cell imaging showed that T40A was not retained in the ER and colocalized with markers for Golgi and endosomes. In contrast, substitution of aspartate or glutamate at Thr40, to mimic phosphorylation, restored normal trafficking to the PM. HEK293 cells transfected with K560 or T40A mutants had 10% of the GABA transport activity of native BGT1, but normal transport activity was restored in cells expressing T40E. Normal BGT1 trafficking likely requires phosphorylation at Thr40 in addition to C-terminal motifs. Christopher R. Day, Sashana S. Gordon, Cherissa L. Vaughn, and Stephen A. Kempson Copyright © 2013 Christopher R. Day et al. All rights reserved. The Small-Conductance Ca2+-Activated Potassium Channel, Subtype SK3, in the Human Myometrium Is Downregulated in Early Stages of Pregnancy Sun, 07 Apr 2013 14:39:18 +0000 http://www.hindawi.com/journals/physiology/2013/584717/ The human myometrium is mainly relaxed during pregnancy, but, up to term, contractions become more coordinated and forceful in order to initiate delivery. Small conductance Ca2+-activated K+ channels (SK channels) in human myometrium have been shown to be downregulated in late pregnancy. The aim was to investigate the presence of SK2 and SK3 in the human myometrium from nonpregnant women, pregnant women at term, and pregnancies delivered preterm and, in addition, to characterize the time of downregulation of these channels. Using qRT-PCR, we observed significantly lower levels of mRNA for SK2 than for SK3 in the nonpregnant tissue. The mRNA levels of SK3 were significantly reduced in tissue from pregnancies at term and pregnancies resulting in preterm deliveries, whereas no downregulation for SK2 was observed. Western blotting confirmed the qRT-PCR results. Using immunohistochemical staining, both SK2 and SK3 were detected in endometrial glandular epithelium. We conclude that SK3 mRNA is downregulated early in pregnancy—at least among those that result in preterm deliveries. Furthermore, we find that SK channels are expressed not only in the uterine smooth muscle but also in the endometrial epithelium. M. Rahbek, S. T. Rosenbaum, M. J. Dahl, D. A. Klaerke, L. Ødum, S. S. Poulsen, T. Larsen, and P. Bouchelouche Copyright © 2013 M. Rahbek et al. All rights reserved. Reliability of the Electromechanical Delay Components Assessment during the Relaxation Phase Wed, 06 Mar 2013 15:12:36 +0000 http://www.hindawi.com/journals/physiology/2013/517838/ The study aimed to assess by an electromyographic (EMG), mechanomyographic (MMG), and force-combined approach the electrochemical and mechanical components of the overall electromechanical delay during relaxation (R-EMD). Reliability of the measurements was also assessed. To this purpose, supramaximal tetanic stimulations (50 Hz) were delivered to the gastrocnemius medialis muscle of 17 participants. During stimulations, the EMG, MMG, and force signals were detected, and the time lag between EMG cessation and the beginning of force decay ( EMG-F, as temporal indicators of the electrochemical events) and from the initial force decrease to the largest negative peak of MMG signal during relaxation ( F-MMG, as temporal indicators of the mechanical events) was calculated, together with overall R-EMD duration (from EMG cessation to the largest MMG negative peak during relaxation). Peak force (pF), half relaxation time (HRT), and MMG peak-to-peak during the relaxation phase (R-MMG p-p) were also calculated. Test-retest reliability was assessed by Intraclass Correlation Coefficient (ICC). With a total R-EMD duration of 96.9 ± 1.9 ms, EMG-F contributed for about 24% (23.4 ± 2.7 ms) while F-MMG for about 76% (73.5 ± 3.2 ms). Reliability of the measurements was high for all variables. Our findings show that the main contributor to R-EMD is represented by the mechanical components (series elastic components and muscle fibres behaviour), with a high reliability level for this type of approach. Emiliano Cè, Susanna Rampichini, Eloisa Limonta, and Fabio Esposito Copyright © 2013 Emiliano Cè et al. All rights reserved. Noninvasive Evaluation of Nerve Conduction in Small Diameter Fibers in the Rat Tue, 26 Feb 2013 15:28:04 +0000 http://www.hindawi.com/journals/physiology/2013/254789/ A novel noninvasive technique was applied to measure velocity within slow conducting axons in the distal extreme of the sciatic nerve (i.e., digital nerve) in a rat model. The technique is based on the extraction of rectified multiple unit activity (MUA) from in vivo whole nerve compound responses. This method reliably identifies compound action potentials in thinly myelinated fibers conducting at a range of 9–18 m/s ( axons), as well as in a subgroup of unmyelinated C fibers conducting at approximately 1-2 m/s. The sensitivity of the method to C-fiber conduction was confirmed by the progressive decrement of the responses in the 1-2 m/s range over a 20-day period following the topical application of capsaicin (ANOVA ). Increasing the frequency of applied repetitive stimulation over a range of 0.75 Hz to 6.0 Hz produced slowing of conduction and a significant decrease in the magnitude of the compound C-fiber response (ANOVA ). This technique offers a unique opportunity for the noninvasive, repeatable, and quantitative assessment of velocity in the subsets of and C fibers in parallel with the evaluation of fast nerve conduction. Elena G. Zotova and Joseph C. Arezzo Copyright © 2013 Elena G. Zotova and Joseph C. Arezzo. All rights reserved. Use of Near Infrared Spectroscopy to Asses Remote Ischemic Preconditioning in Skeletal Muscle Thu, 21 Feb 2013 14:20:42 +0000 http://www.hindawi.com/journals/physiology/2013/154327/ Remote ischemic preconditioning (IPC) is a procedure during which brief periods of ischemia protect distant organ from ischemia-reperfusion injury. Appling IPC on an upper arm, this phenomenon has been demonstrated in several studies. Skeletal muscle tissue oxygenation at rest (StO2) and StO2 deoxygenation rate during vascular occlusion can be measured using near infrared spectroscopy (NIRS). We aimed to investigate the effects of remote upper arm IPC on StO2 and flow-mediated dilatation (FMD) in healthy male volunteers. In a randomized controlled crossover trial, resting StO2, StO2 deoxygenation rate, and FMD were measured on testing arm at baseline and after 60 minutes. After basal measurements IPC protocol on a contralateral arm was performed. StO2 deoxygenation rate was significantly lower after remote, the IPC cycles in comparison to deoxygenation rate at baseline ( versus %, ). Comparison of deoxygenation rates showed a significant difference between the IPC and the control protocol (, ). No differences were observed in FMD before and after remote IPC and in the control protocol. In healthy young adults, remote IPC reduces StO2 deoxygenation rate but has no significant impact on FMD. NIRS technique offers a novel approach to asses skeletal muscle adaptation in response to remote ischemic stimuli. Jana Ambrozic, Mitja Lainscak, and Matej Podbregar Copyright © 2013 Jana Ambrozic et al. All rights reserved. Combined Lung Transfer of NO and CO in Patients Receiving Methotrexate or Bleomycin Therapy Compared to Normal Subjects Tue, 29 Jan 2013 14:25:10 +0000 http://www.hindawi.com/journals/physiology/2013/539076/ The first aim of the study is to determine whether combined lung diffusing capacities of nitric oxide (TLNO) and of carbon monoxide (TLCO) are accurate in the followup of patients receiving either methotrexate (MTX) or bleomycin (BLM). The second objective is to determine whether TLCO, TLNO, KCO, and TLCO/VI% (inspiratory volume expressed as percentage of predicted value) correlate better with the diffusing capacity of the membrane (Dm) and/or capillary lung volume (Vc). TLNO and TLCO were measured in three groups: 22 “normal” subjects (N group), 17 patients receiving MTX, and 12 patients treated with BLM. TLCO, TLNO, Dm, and Vc were much lower in the MTX and BLM groups compared to those of the N one. The ratio TLNO/TLCO was higher in the BLM group compared to that of the N group and compared to that of the MTX group. KCO correlated neither with Dc nor with Vc, whereas TLCO/VI% correlated significantly with both Dm and Vc. Combined measurement of TLCO and TLNO seems to be useful in the followup of patients receiving agents inducing lung toxicity and gives a good idea of the alveolar membrane and the capillary volume. Chantal Viart-Ferber, Sébastien Couraud, Frédéric Gormand, and Yves Pacheco Copyright © 2013 Chantal Viart-Ferber et al. All rights reserved. Effect of Aerobic Training on Cognitive Function and Arterial Stiffness in Sedentary Young Adults: A Pilot Randomized Controlled Trial Mon, 14 Jan 2013 08:19:42 +0000 http://www.hindawi.com/journals/physiology/2013/847325/ This study measured cognitive and vascular responses to aerobic training in sedentary young adults. Ten adults (6 women, 4 men; 18–29 years) were randomly assigned to an experimental or no-treatment control group. The experimental group engaged in a 6-week intervention, performed on exercise cycle and treadmill, 3x/week, 50 min/session; intensity was increased over time. Outcome measures included arterial stiffness (augmentation index, AIx, and pulse pressure), cardiorespiratory fitness (), and cognitive function (attention, processing speed, working memory, episodic memory, and executive function). Participants randomized to aerobic training improved processing speed versus control (, ES = 0.55). However, no group × time effects were noted in other domains of cognitive function. AIx was reduced by approximately 16% from before to after intervention in the experimental group; however, the improvement was not statistically significant versus control (, ES = 0.22). Pulse pressure did not change between groups over time (, ES = 0.0). increased by approximately 10% in the experimental group; however, the change was not significant between groups over time (, ES = 0.27). Vascular and cognitive adaptations to aerobic training may move in parallel. Robust trials simultaneously investigating a broad spectrum of aerobic training interventions and vascular and cognitive outcomes are warranted. Samuel Asamoah, Jason Siegler, Dennis Chang, Andrew Scholey, Alan Yeung, and Birinder S. Cheema Copyright © 2013 Samuel Asamoah et al. All rights reserved.