bluuebunny/crossref_metadata_2025 huggingface dataset:
Normalized force, activation, and coactivation in the arm muscles of young and old men
Authors: Klein C. S. , Rice C. L. , Marsh G. D.
Published: December 2017

The purpose of this study was to determine whether the loss of muscle strength in the elderly could be explained entirely by a decline in the physiological cross-sectional area (PCSA) of muscle. Isometric force, muscle activation (twitch interpolation), and coactivation (surface electromyograph) were measured during maximal voluntary contractions (MVCs) of the elbow flexors (EFs) and extensors (EEs) in 20 young (23 ± 3 yr) and 13 older (81 ± 6 yr) healthy men. PCSA was determined using magnetic resonance imaging, and normalized force (NF) was calculated as the MVC/PCSA ratio. The PCSA was smaller in the old compared with the young men, more so in the EEs (28%) compared with the EFs (19%) ( P < 0.001); however, the decline in MVC (∼30%) with age was similar in the two muscle groups. Muscle activation was not different between the groups, but coactivation was greater (5%) ( P < 0.001) in the old men for both muscles. NF was less (11%) in the EFs ( P < 0.01) and tended to be unchanged in the EEs of the old compared with young subjects. The relative maintenance of NF in the EEs compared with the EFs may be related to age-associated changes in the architecture of the triceps brachii muscle. In conclusion, although the decline in PCSA explained the majority of strength loss in the old men, additional factors such as greater coactivation or reduced specific tension also may have contributed to the age-related loss of isometric strength.
Invited Review: Mechanisms of calcium handling in smooth muscles
Authors: Sanders Kenton M.
Published: December 2017

The concentration of cytoplasmic Ca2+regulates the contractile state of smooth muscle cells and tissues. Elevations in global cytoplasmic Ca2+resulting in contraction are accomplished by Ca2+entry and release from intracellular stores. Pathways for Ca2+entry include dihydropyridine-sensitive and -insensitive Ca2+channels and receptor and store-operated nonselective channels permeable to Ca2+. Intracellular release from the sarcoplasmic reticulum (SR) is accomplished by ryanodine and inositol trisphosphate receptors. The impact of Ca2+entry and release on cytoplasmic concentration is modulated by Ca2+reuptake into the SR, uptake into mitochondria, and extrusion into the extracellular solution. Highly localized Ca2+transients (i.e., sparks and puffs) regulate ionic conductances in the plasma membrane, which can provide feedback to cell excitability and affect Ca2+entry. This short review describes the major transport mechanisms and compartments that are utilized for Ca2+handling in smooth muscles.
Selected Contribution: Insulin utilizes NO/cGMP pathway to activate myosin phosphatase via Rho inhibition in vascular smooth muscle
Authors: Sandu Oana A. , Ito Masaaki , Begum Najma
Published: December 2017

Our laboratory has recently demonstrated that insulin induces relaxation of vascular smooth muscle cells (VSMCs) by activating myosin-bound phosphatase (MBP) and by inhibiting Rho kinase (Begum N, Duddy N, Sandu OA, Reinzie J, and Ragolia L. Mol Endocrinol14: 1365–1376, 2000). In this study, we tested the hypothesis that insulin via the nitric oxide (NO)/cGMP pathway may inactivate Rho, resulting in a decrease in phosphorylation of the myosin-bound subunit (MBSThr695) of MBP and in its activation. Treatment of confluent serum-starved VSMCs with insulin prevented thrombin-induced increases in membrane-associated RhoA, Rho kinase activation, and site-specific phosphorylation of MBSThr695of MBP and caused MBP activation. Preexposure to NG-monomethyl-l-arginine, a NO synthase inhibitor, and R- p-8-(4-chlorophenylthio)cGMP, a cGMP antagonist, attenuated insulin's inhibitory effect on Rho translocation and restored thrombin-mediated Rho kinase activation and site-specific MBSThr695phosphorylation, resulting in MBP inactivation. In contrast, 8-bromo-cGMP, a cGMP agonist, mimicked insulin's inhibitory effects by abolishing thrombin-mediated Rho signaling and promoted dephosphorylation of MBSThr695. Furthermore, expression of a dominant-negative RhoA decreased basal as well as thrombin-induced MBSThr695phosphorylation and caused insulin activation of MBP. Collectively, these results indicate that insulin inhibits Rho signaling by decreasing RhoA translocation via the NO/cGMP signaling pathway to cause MBP activation via site-specific dephosphorylation of its regulatory subunit MBS.
Glibenclamide improves postischemic recovery of myocardial contractile function in trained and sedentary rats
Authors: Jew Korinne N. , Moore Russell L.
Published: December 2017

In this study, we sought to determine whether there was any evidence for the idea that cardiac ATP-sensitive K+ (KATP) channels play a role in the training-induced increase in the resistance of the heart to ischemia-reperfusion (I/R) injury. To do so, the effects of training and an KATP channel blocker, glibenclamide (Glib), on the recovery of left ventricular (LV) contractile function after 45 min of ischemia and 45 min of reperfusion were examined. Female Sprague-Dawley rats were sedentary (Sed; n = 18) or were trained (Tr; n = 17) for >20 wk by treadmill running, and the hearts from these animals used in a Langendorff-perfused isovolumic LV preparation to assess contractile function. A significant increase in the amount of 72-kDa class of heat shock protein was observed in hearts isolated from Tr rats. The I/R protocol elicited significant and substantial decrements in LV developed pressure (LVDP), minimum pressure (MP), rate of pressure development, and rate of pressure decline and elevations in myocardial Ca2+ content in both Sed and Tr hearts. In addition, I/R elicited a significant increase in LV diastolic stiffness in Sed, but not Tr, hearts. When administered in the perfusate, Glib (1 μM) elicited a normalization of all indexes of LV contractile function and reductions in myocardial Ca2+content in both Sed and Tr hearts. Training increased the functional sensitivity of the heart to Glib because LVDP and MP values normalized more quickly with Glib treatment in the Tr than the Sed group. The increased sensitivity of Tr hearts to Glib is a novel finding that may implicate a role for cardiac KATP channels in the training-induced protection of the heart from I/R injury.
PI3-kinase/Akt modulates vascular smooth muscle tone via cAMP signaling pathways
Authors: Komalavilas Padmini , Mehta Shyamal , Wingard Christopher J. , Dransfield Daniel T. , Bhalla Jyoti , Woodrum Julie E. , Molinaro Jason R. , Brophy Colleen M.
Published: December 2017

Phosphatidylinositol 3-kinase (PI3-kinase) activates protein kinase B (also known as Akt), which phosphorylates and activates a cyclic nucleotide phosphodiesterase 3B. Increases in cyclic nucleotide concentrations inhibit agonist-induced contraction of vascular smooth muscle. Thus we hypothesized that the PI3-kinase/Akt pathway may regulate vascular smooth muscle tone. In unstimulated, intact bovine carotid artery smooth muscle, the basal phosphorylation of Akt was higher than that in cultured smooth muscle cells. The phosphorylation of Akt decreases in a time-dependent manner when incubated with the PI3-kinase inhibitor, LY-294002. Agonist (serotonin)-, phorbol ester (phorbol 12,13-dibutyrate; PDBu)-, and depolarization (KCl)-induced contractions of vascular smooth muscles were all inhibited in a dose-dependent fashion by LY-294002. However, LY-294002 did not inhibit serotonin- or PDBu-induced increases in myosin light chain phosphorylation or total O2consumption, suggesting that inhibition of contraction was not mediated by reversal or inhibition of the pathways that lead to smooth muscle activation and contraction. Treatment of vascular smooth muscle with LY-294002 increased the activity of cAMP-dependent protein kinase and increased the phosphorylation of the cAMP-dependent protein kinase substrate heat shock protein 20 (HSP20). These data suggest that activation of the PI3-kinase/Akt pathway in unstimulated smooth muscle may modulate vascular smooth muscle tone (allow agonist-induced contraction) through inhibition of the cyclic nucleotide/HSP20 pathway and suggest that cyclic nucleotide-dependent inhibition of contraction is dissociated from the myosin light chain contractile regulatory pathways.
Volume displaced by diaphragm motion in emphysema
Authors: Singh Bhajan , Eastwood Peter R. , Finucane Kevin E.
Published: December 2017

To examine the effect of hyperinflation on the volume displaced by diaphragm motion (ΔVdi), we compared nine subjects with emphysema and severe hyperinflation [residual volume (RV)/total lung capacity (TLC) 0.65 ± 0.08; mean ± SD] with 10 healthy controls. Posteroanterior and lateral chest X rays at RV, functional residual capacity, one-half inspiratory capacity, and TLC were used to measure the length of diaphragm apposed to ribcage (Lap), cross-sectional area of the pulmonary ribcage, ΔVdi, and volume beneath the lung-apposed dome of the diaphragm. Emphysema subjects, relative to controls, had increased Lap at comparable lung volumes (4.3 vs. 1.0 cm near predicted TLC, 95% confidence interval 3.4–5.2 vs. 0–2.1), pulmonary rib cage cross-sectional area (emphysema/controls 1.22 ± 0.03, P < 0.001 at functional residual capacity), and ΔVdi/ΔLap (0.25 vs. 0.14 liters/cm, P < 0.05). During a vital capacity inspiration, relative to controls, ΔVdi was normal in five (1.94 ± 0.51 liters) and decreased in four (0.51 ± 0.40 liters) emphysema subjects, and volume beneath the dome did not increase in emphysema (0 ± 0.36 vs. 0.82 ± 0.80 liters, P < 0.05). We conclude that ΔVdi can be normal in emphysema because 1) hyperinflation is shared between ribcage and diaphragm, preserving Lap, and 2) the diaphragm remains flat during inspiration.
Pulmonary and bronchial circulations: contributions to heat and water exchange in isolated lungs
Authors: Serikov V. B. , Fleming N. W.
Published: December 2017

The relative contribution of the pulmonary and bronchial circulatory systems to heat and water exchange in normal lungs was evaluated in 20 isolated, in situ perfused dog lungs and in four patients undergoing elective cardiopulmonary bypass. In isolated dog lungs, if the pulmonary artery was perfused at a nominal flow rate (0.5 l/min), bronchial artery perfusion (up to 70 ml/min) did not significantly affect the expired gas temperature. When the lungs were not perfused through either system, 8 min of ventilation with cool, dry gas decreased the temperature of the expired gas by 6.2 ± 1.4°C. Selective perfusion of bronchial arteries at 68 ± 10 mmHg resulted in a mean flow rate of 28 ± 16 ml/min and increased the average temperature of the expired gas by 0.6°C. An increase in the rate of bronchial arterial perfusion to 55 ± 14 ml/min increased the average temperature of the expired gas by 1.3°C. The time constant for equilibration of tritiated water between the perfusate and the lung parenchyma was 130 ± 33 min for pulmonary arterial perfusion and 35 ± 13 min for combined bronchial and pulmonary perfusion, which indicated that filtration of water from high-pressure bronchial vessels facilitated water exchange in the lung interstitium. The rate of tracer equilibration was similar between the perfusate and gas in both variants of perfusion, but the ratios of tracer gas to perfusate were different (0.42 ± 0.06 for pulmonary, 0.98 ± 0.07 for combined), which indicates that bronchial vessels contribute mainly to the hydration of the bronchial mucosa. In humans, the bronchial blood flow was capable of maintaining heat supply after the initiation of cardiopulmonary bypass. Before bypass, when both pulmonary and bronchial blood flow were present, the mean time constant of the temperature decay after a switch to ventilation with cool, dry gas was 35 ± 12 s. The average temperature difference between the blood and expired gas was 2.4 ± 0.50°C. After 5 min of dry gas ventilation, the temperature difference between the expired gas and initial blood temperature decreased an average of 3.8 ± 0.06°C ( P < 0.05). The time constant of temperature decay increased to 56 ± 14 s ( P < 0.05). We conclude that bronchial perfusion has a less important role in the temperature balance of the respiratory tract compared with pulmonary arterial perfusion because heat flux is “flow limited” but is important in providing water for hydration of the mucosal surface and interstitial compartments of peribronchial tissues.
AMP-activated protein kinase activation prevents denervation-induced decline in gastrocnemius GLUT-4
Authors: Paulsen S. R. , Rubink D. S. , Winder W. W.
Published: December 2017

This study was designed to determine whether the reductions in GLUT-4 seen in 3-day-denervated muscles can be prevented through chemical activation of 5′-AMP-activated protein kinase (AMPK). Muscle AMPK can be chemically activated in rats using subcutaneous injections with 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR). In this study, the tibial nerve was sectioned on one side; the other was sham operated but without nerve section. Acute injections of AICAR resulted in significantly increased AMPK activity in denervated gastrocnemius but not soleus muscles. Acetyl-CoA carboxylase activity, a reporter of AMPK activation, declined in both gastrocnemius and soleus in both denervated and contralateral muscles. Three days after denervation, GLUT-4 levels were significantly decreased by ∼40% in gastrocnemius muscles and by ∼30% in soleus muscles. When rats were injected with AICAR (1 mg/g body wt) for 3 days, the decline in GLUT-4 levels was prevented in denervated gastrocnemius muscles but not in denervated soleus muscles. The extent of denervation-induced muscle atrophy was similar in AICAR-treated vs. saline-treated rats. These studies provide evidence that some effects of denervation may be prevented by chemical activation of the appropriate signaling pathways.
Effect of carbohydrate ingestion on metabolism during running and cycling
Authors: Arkinstall Melissa J. , Bruce Clinton R. , Nikolopoulos Vasilis , Garnham Andrew P. , Hawley John A.
Published: December 2017

The effects of carbohydrate or water ingestion on metabolism were investigated in seven male subjects during two running and two cycling trials lasting 60 min at individual lactate threshold using indirect calorimetry, U-14C-labeled tracer-derived measures of the rates of oxidation of plasma glucose, and direct determination of mixed muscle glycogen content from the vastus lateralis before and after exercise. Subjects ingested 8 ml/kg body mass of either a 6.4% carbohydrate-electrolyte solution (CHO) or water 10 min before exercise and an additional 2 ml/kg body mass of the same fluid after 20 and 40 min of exercise. Plasma glucose oxidation was greater with CHO than with water during both running (65 ± 20 vs. 42 ± 16 g/h; P < 0.01) and cycling (57 ± 16 vs. 35 ± 12 g/h; P < 0.01). Accordingly, the contribution from plasma glucose oxidation to total carbohydrate oxidation was greater during both running (33 ± 4 vs. 23 ± 3%; P < 0.01) and cycling (36 ± 5 vs. 22 ± 3%; P < 0.01) with CHO ingestion. However, muscle glycogen utilization was not reduced by the ingestion of CHO compared with water during either running (112 ± 32 vs. 141 ± 34 mmol/kg dry mass) or cycling (227 ± 36 vs. 216 ± 39 mmol/kg dry mass). We conclude that, compared with water, 1) the ingestion of carbohydrate during running and cycling enhanced the contribution of plasma glucose oxidation to total carbohydrate oxidation but 2) did not attenuate mixed muscle glycogen utilization during 1 h of continuous submaximal exercise at individual lactate threshold.
Changes in cerebral oxygenation and blood flow during LBNP in spinal cord-injured individuals
Authors: Houtman Sibrand , Serrador Jorge M. , Colier Willy N. J. M. , Strijbos Derek W. , Shoemaker Kevin , Hopman Maria T. E.
Published: December 2017

Spinal cord-injured (SCI) individuals, having a sympathetic nervous system lesion, experience hypotension during sitting and standing. Surprisingly, they experience few syncopal events. This suggests adaptations in cerebrovascular regulation. Therefore, changes in systemic circulation, cerebral blood flow, and oxygenation in eight SCI individuals were compared with eight able-bodied (AB) individuals. Systemic circulation was manipulated by lower body negative pressure at several levels down to −60 mmHg. At each level, we measured steady-state blood pressure, changes in cerebral blood velocity with transcranial Doppler, and cerebral oxygenation using near-infrared spectroscopy. We found that mean arterial pressure decreased significantly in SCI but not in AB individuals, in accordance with the sympathetic impairment in the SCI group. Cerebral blood flow velocity decreased during orthostatic stress in both groups, but this decrease was significantly greater in SCI individuals. Cerebral oxygenation decreased in both groups, with a tendency to a greater decrease in SCI individuals. Thus present data do not support an advantageous mechanism during orthostatic stress in the cerebrovascular regulation of SCI individuals.
No effect of mild heat stress on the regulation of carbohydrate metabolism at the onset of exercise
Authors: Saunders P. U. , Watt M. J. , Garnham A. P. , Spriet L. L. , Hargreaves M. , Febbraio M. A.
Published: December 2017

To investigate the influence of heat stress on the regulation of skeletal muscle carbohydrate metabolism, six active, but not specifically trained, men performed 5 min of cycling at a power output eliciting 70% maximal O2uptake in either 20°C (Con) or 40°C (Heat) after 20 min of passive exposure to either environmental condition. Although muscle temperature (Tmu) was similar at rest when comparing trials, 20 min of passive exposure and 5 min of exercise increased ( P < 0.05) Tmuin Heat compared with Con (37.5 ± 0.1 vs. 36.9 ± 0.1°C at 5 min for Heat and Con, respectively). Rectal temperature and plasma epinephrine were not different at rest, preexercise, or 5 min of exercise between trials. Although intramuscular glycogen phosphorylase and pyruvate dehydrogenase activity increased ( P < 0.05) at the onset of exercise, there were no differences in the activities of these regulatory enzymes when comparing Heat with Con. Accordingly, glycogen use in the first 5 min of exercise was not different when comparing Heat with Con. Similarly, no differences in intramuscular concentrations of glucose 6-phosphate, lactate, pyruvate, acetyl-CoA, creatine, phosphocreatine, or ATP were observed at any time point when comparing Heat with Con. These results demonstrate that, whereas mild heat stress results in a small difference in contracting Tmu, it does not alter the activities of the key regulatory enzymes for carbohydrate metabolism or glycogen use at the onset of exercise, when plasma epinephrine levels are unaltered.
Age does not influence muscle fiber length adaptation to increased excursion
Authors: Burkholder Thomas J.
Published: December 2017

Muscle fiber length adaptation to static stretch or shortening depends on age, with sarcomere addition in young muscle being dependent on mobility. Series sarcomere number can also increase in young animals in response to increased muscle excursion, but it is not clear whether adult muscles respond similarly. The ankle flexor retinaculum was transected in neonatal and adult rats to increase tibialis anterior muscle excursion. Sarcomere number in tibialis anterior was determined after 8 wk of adaptation. Muscle moment arm and excursion were increased 30% ( P < 0.01) in both age groups. Muscle cross-sectional area was reduced by 12% ( P < 0.01) in response to the increased mechanical advantage, and this reduction was unaffected by age. Fiber length change was also unaffected by age, with both groups showing a trend ( P < 0.10) for slightly (6%) increased fiber length. Retinaculum transection results in shorter muscle length in all joint configurations, so this trend opposes the fiber length decrease predicted by an adaptation to muscle length and indicates that fiber length is influenced by dynamic mechanical signals in addition to static length.
Effect of estrogen on flow-induced dilation in NO deficiency: role of prostaglandins and EDHF
Authors: Huang An , Wu Yuming , Sun Dong , Koller Akos , Kaley Gabor
Published: December 2017

To investigate the role of estrogen in flow-induced dilation (FiD) in nitric oxide (NO) deficiency, FiD was examined in isolated gracilis arterioles of ovariectomized (OVX) and OVX rats with estrogen replacement (OVE). Both groups of rats were treated chronically with Nω-nitro-l-arginine methyl ester. Plasma concentration of NO2/NO3was reduced in both groups. Plasma concentration of estradiol was lower in OVX than in OVE rats. FiD was similar in vessels of the two groups; calculated wall shear stress and basal tone were significantly greater in OVX vs. OVE rats. Indomethacin did not affect FiD in vessels from OVE rats but abolished dilation in vessels from OVX rats. Valeryl salicylate or NS-398 inhibited FiD by ∼50%, whereas their simultaneous administration eliminated the response in arterioles from OVX rats. In vessels from OVE rats, miconazole or charybdotoxin eliminated FiD. Thus, in NO deficiency, prostaglandins derived from both cyclooxygenase isoforms mediate FiD in gracilis arterioles of OVX rats. Estrogen replacement switches the mediation, showing dependence on endothelium-derived hyperpolarizing factor in the arterioles of OVE rats.
Effect of epinephrine on net lactate uptake by contracting skeletal muscle
Authors: Hamann Jason J. , Kelley Kevin M. , Gladden L. Bruce
Published: December 2017

The purpose of this study was to determine the effect of epinephrine on net lactate (La−) uptake at constant elevated blood La− concentration and steady level metabolic rate (O2 uptake) in the canine gastrocnemius-plantaris muscle in situ. Infusion of La−/lactic acid (pH 3.5) established a mean arterial blood La− concentration of ∼10 mM while normal blood-gas and pH status were maintained as the gastrocnemius-plantaris was stimulated with tetanic trains at a rate of one contraction every 4 s. After steady-state control measures, epinephrine was infused for 35 min at rates that produced a high physiological concentration with (Pro; n = 6) and without (Epi; n = 6) β-adrenergic-receptor blockade via propranolol. Net La−uptake values during the control conditions were not significantly different between trials (Epi: 0.756 ± 0.043; Pro: 0.703 ± 0.061 mmol · kg−1 · min−1). Steady level O2 uptake averaged ∼69.5 ml · kg−1 · min−1 for both control conditions and did not significantly change over the course of the experiments in either set of trials. Epi experiments resulted in a significantly reduced net La− uptake (0.346 ± 0.088 mmol · kg−1 · min−1 after 5 min of infusion) compared with control value at all sample times measured. However, net La− uptake was not significantly different from control at any time during Pro (0.609 ± 0.052 mmol · kg−1 · min−1 after 5 min of infusion). When the change from the respective control values for net La− uptake was compared across time for both series of experiments, Epi resulted in a significantly greater change from control than did Pro. This study suggests that epinephrine can have a profound effect on net La− uptake by contracting muscle and that these effects are elicited through β-adrenergic-receptor stimulation.
Electro-hydrodynamic atomization of drug solutions for inhalation purposes
Authors: Ijsebaert Jeroen C. , Geerse Kees B. , Marijnissen Jan C. M. , Lammers Jan-Willem J. , Zanen Pieter
Published: December 2017

Monodisperse aerosols show therapeutic advantages, but they are difficult to generate. A new method (electrohydrodynamic atomization) is described. A high voltage is applied to a nozzle through which a solution, containing dissolved drug, is pumped. At the nozzle tip, a liquid cone is formed and a stream of monodisperse droplets is released. The droplet diameter is governed by the density, conductivity, and the flow rate of the fluid. The droplets are charged and need to be neutralized. Therefore, a corona discharge system is used. Methylparahydroxybenzoate was used as a model drug, and additional data were generated by using beclomethasone dipropionate (BDP). At a flow rate of 1 ml/h and 0.5% methylparahydroxybenzoate, 1.58-μm particles were produced with a geometric SD of 1.18. Increasing the flow rate to 3 ml/h and the concentration to 3% resulted in 4.55-μm particles with a geometric SD of 1.29. The experiments with BDP resulted in similar particle sizes. The mass of BDP was found to range between 1.42 and 6 μg/l air. Aqueous solutions cannot be sprayed by using this setup. This method can be used to deliver antiasthma drugs to patients.
Long-term facilitation in obstructive sleep apnea patients during NREM sleep
Authors: Aboubakr Salah E. , Taylor Amy , Ford Reason , Siddiqi Sarosh , Badr M. Safwan
Published: December 2017

Repetitive hypoxia followed by persistently increased ventilatory motor output is referred to as long-term facilitation (LTF). LTF is activated during sleep after repetitive hypoxia in snorers. We hypothesized that LTF is activated in obstructive sleep apnea (OSA) patients. Eleven subjects with OSA (apnea/hypopnea index = 43.6 ± 18.7/h) were included. Every subject had a baseline polysomnographic study on the appropriate continuous positive airway pressure (CPAP). CPAP was retitrated to eliminate apnea/hypopnea but to maintain inspiratory flow limitation (sham night). Each subject was studied on 2 separate nights. These two studies are separated by 1 mo of optimal nasal CPAP treatment for a minimum of 4–6 h/night. The device was capable of covert pressure monitoring. During night 1 (N1), study subjects used nasal CPAP at suboptimal pressure to have significant air flow limitation (>60% breaths) without apneas/hypopneas. After stable sleep was reached, we induced brief isocapnic hypoxia [inspired O2 fraction (Fi O2 ) = 8%] (3 min) followed by 5 min of room air. This sequence was repeated 10 times. Measurements were obtained during control, hypoxia, and at 5, 20, and 40 min of recovery for ventilation, timing ( n = 11), and supraglottic pressure ( n = 6). Upper airway resistance (Rua) was calculated at peak inspiratory flow. During the recovery period, there was no change in minute ventilation (99 ± 8% of control), despite decreased Rua to 58 ± 24% of control ( P < 0.05). There was a reduction in the ratio of inspiratory time to total time for a breath (duty cycle) (0.5 to 0.45, P < 0.05) but no effect on inspiratory time. During night 2 (N2), the protocol of N1 was repeated. N2 revealed no changes compared with N1 during the recovery period. In conclusion, 1) reduced Rua in the recovery period indicates LTF of upper airway dilators; 2) lack of hyperpnea in the recovery period suggests that thoracic pump muscles do not demonstrate LTF; 3) we speculate that LTF may temporarily stabilize respiration in OSA patients after repeated apneas/hypopneas; and 4) nasal CPAP did not alter the ability of OSA patients to elicit LTF at the thoracic pump muscle.
In vivo determination of fascicle curvature in contracting human skeletal muscles
Authors: Muramatsu Tadashi , Muraoka Tetsuro , Kawakami Yasuo , Shibayama Akira , Fukunaga Tetsuo
Published: December 2017

Fascicle curvature of human medial gastrocnemius muscle (MG) was determined in vivo by ultrasonography during isometric contractions at three (distal, central, and proximal) locations ( n = 7) and at three ankle angles ( n = 7). The curvature significantly ( P < 0.05) increased from rest to maximum voluntary contraction (MVC) (0.4–5.2 m−1). In addition, the curvature at MVC became larger in the order dorsiflexed, neutral, plantar flexed ( P < 0.05). Thus both contraction levels and muscle length affected the curvature. Intramuscular differences in neither the curvature nor the fascicle length were found. The direction of curving was consistent along the muscle: fascicles were concave in the proximal side. Fascicle length estimated from the pennation angle and muscle thickness, under the assumption that the fascicle was straight, was underestimated by ∼6%. In addition, the curvature was significantly correlated to pennation angle and muscle thickness. These findings are particularly important for understanding the mechanical functions of human skeletal muscle in vivo.
Effects of moderate heart failure and functional overload on rat plantaris muscle
Authors: Spangenburg Espen E. , Lees Simon J. , Otis Jeff S. , Musch Timothy I. , Talmadge Robert J. , Williams Jay H.
Published: December 2017

It is thought that changes in sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) of skeletal muscle contribute to alterations in skeletal muscle function during congestive heart failure (CHF). It is well established that exercise training can improve muscle function. However, it is unclear whether similar adaptations will result from exercise training in a CHF patient. Therefore, the purpose of this study was to determine whether skeletal muscle during moderate CHF adapts to increased activity, utilizing the functional overload (FO) model. Significant increases in plantaris mass of the CHF-FO and sham-FO groups compared with the CHF and control (sham) groups were observed. Ca2+uptake rates were significantly elevated in the CHF group compared with all other groups. No differences were detected in Ca2+uptake rates between the CHF-FO, sham, and sham-FO groups. Increases in Ca2+uptake rates in moderate-CHF rats were not due to changes in SERCA isoform proportions; however, FO may have attenuated the CHF-induced increases through alterations in SERCA isoform expression. Therefore, changes in skeletal muscle Ca2+handling during moderate CHF may be due to alterations in regulatory mechanisms, which exercise may override, by possibly altering SERCA isoform expression.
Tissue factor-dependent pathway is not involved in exercise-induced formation of thrombin and fibrin
Authors: Weiss Claus , Bierhaus Angelika , Kinscherf Ralf , Hack Volker , Luther Thomas , Nawroth Peter Paul , Bärtsch Peter
Published: December 2017

In healthy individuals, prolonged intensive physical exercise leads to an activation of blood coagulation that results in the formation of thrombin and fibrin. This study investigated whether oxidative stress during intensive physical exercise induces tissue factor (TF) via activation of the redox-responsive transcription factor nuclear factor-κB (NF-κB). Twelve young men performed a standardized 1-h maximal run on a treadmill that gave rise to significant increases of markers of thrombin and fibrin formation. The ratio of intracellular reduced to oxidized glutathione as measured by HPLC decreased from 23.3 ± 10.7 to 14.2 ± 6.5 ( P < 0.05), indicating the generation of free radicals during exercise. Electrophoretic mobility shift assays from nuclear extracts of peripheral blood mononuclear cells revealed that exercise testing increased NF-κB (p50/p65) binding activity to a NF-κB consensus sequence by 105 ± 68% ( P < 0.01) but did not affect NF-κB (p65/c-Rel) binding to a nonconsensus-κB-like site present in the TF promoter. Consistently, there was no exercise-induced increase in TF expression as demonstrated by TF-specific immunofluorescence staining and ELISA. Thus selective activation of NF-κB (p50/p65) during intensive physical exercise does not result in the expression of TF, suggesting that the TF-dependent pathway in peripheral blood mononuclear cells does not account for exercise-induced formation of thrombin and fibrin.
Motor unit recruitment strategies investigated by surface EMG variables
Authors: Farina Dario , Fosci Mauro , Merletti Roberto
Published: December 2017

During isometric contractions of increasing strength, motor units (MUs) are recruited by the central nervous system in an orderly manner starting with the smallest, with muscle fibers that usually show the lowest conduction velocity (CV). Theory predicts that the higher the velocity of propagation of the action potential, the higher the power at high frequencies of the detected surface signal. These considerations suggest that the power spectral density of the surface detected electromyogram (EMG) signal may give indications about the MU recruitment process. The purpose of this paper is to investigate the potential and limitations of spectral analysis of the surface EMG signal as a technique for the investigation of muscle force control. The study is based on a simulation approach and on an experimental investigation of the properties of surface EMG signals detected from the biceps brachii during isometric linearly increasing torque contractions. Both simulation and experimental data indicate that volume conductor properties play an important role as confounding factors that may mask any relation between EMG spectral variables and estimated CV as a size principle parameter during ramp contractions. The correlation between spectral variables and CV is thus significantly lower when the MU pool is not stable than during constant-torque isometric contractions. Our results do not support the establishment of a general relationship between spectral EMG variables and torque or recruitment strategy.
Calcium metabolism and cardiovascular function after spaceflight
Authors: Hatton Daniel C. , Yue Qi , Dierickx Jacqueline , Roullet Chantal , Otsuka Keiichi , Watanabe Mitsuaki , Coste Sarah , Roullet Jean Baptiste , Phanouvang Thongchan , Orwoll Eric , Orwoll Shiela , McCarron David A.
Published: December 2017

To determine the influence of dietary calcium on spaceflight-induced alterations in calcium metabolism and blood pressure (BP), 9-wk-old spontaneously hypertensive rats, fed either high- (2%) or low-calcium (0.02%) diets, were flown on an 18-day shuttle flight. On landing, flight animals had increased ionized calcium ( P < 0.001), elevated parathyroid hormone levels ( P < 0.001), reduced calcitonin levels ( P < 0.05), unchanged 1,25(OH)2D3levels, and elevated skull ( P < 0.01) and reduced femur bone mineral density. Basal and thrombin-stimulated platelet free calcium (intracellular calcium concentration) were also reduced ( P < 0.05). There was a tendency for indirect systolic BP to be reduced in conscious flight animals ( P = 0.057). However, mean arterial pressure was elevated ( P < 0.001) after anesthesia. Dietary calcium altered all aspects of calcium metabolism ( P < 0.001), as well as BP ( P < 0.001), but the only interaction with flight was a relatively greater increase in ionized calcium in flight animals fed low- compared with high-calcium diets ( P < 0.05). The results indicate that 1) flight-induced disruptions of calcium metabolism are relatively impervious to dietary calcium in the short term, 2) increased ionized calcium did not normalize low-calcium-induced elevations of BP, and 3) parathyroid hormone was paradoxically increased in the high-calcium-fed flight animals after landing.
Development of an Estimation Instrument of Acoustic Lens Properties for Medical Ultrasound Transducers
Authors: Choi Hojong , Jeong Jongseon Johnson , Kim Jungsuk
Published: December 2017

In medical ultrasound transducers, the transmission mode (pass-through) approach has been used to estimate the characteristics of the acoustic lens. However, it is difficult to measure the acoustic lens properties with high precision because of human, systemic, or mechanical measurement errors. In this paper, we propose a low-cost estimation instrument for acoustic lens properties connected with a customized database. In the instrument, three-axis and one-axis transmitting and material fixtures accurately align the transmitting and receiving transducers separately. Through the developed instrument, we obtained a precise standard deviation of the attenuation coefficient and velocity of the acoustic lens material of 0.05 dB/cm and 2.62 m/s, respectively. Additionally, the simultaneous alignment between the fixtures is controllable with developed programs, thus generating very accurate information of the acoustic lens about the testing ultrasound transducer. In our instrument, the database could support users in managing the result data efficiently. User programs developed using LabVIEW provide the capability to obtain precise values of the attenuation coefficient and velocity, which represent the fundamental material characteristics of the acoustic lens of the medical ultrasound transducers. The developed review program of the customized database can also search the acoustic lens information and store the experimental results.
Neonatal Systemic Inflammation Induces Inflammatory Reactions and Brain Apoptosis in a Pathogen-Specific Manner
Authors: Falck Mari , Osredkar Damjan , Wood Thomas Ragnar , Maes Elke , Flatebø Torun , Sabir Hemmen , Thoresen Marianne
Published: December 2017

Background: After neonatal asphyxia, therapeutic hypothermia (HT) is the only proven treatment option. Although established as a neuroprotective therapy, benefit from HT has been questioned when infection is a comorbidity to hypoxic-ischaemic (HI) brain injury. Gram-negative and gram-positive species activate the immune system through different pathogen recognition receptors and subsequent immunological systems. In rodent models, gram-negative (lipopolysaccharide [LPS]) and gram-positive (PAM3CSK4 [PAM]) inflammation similarly increase neuronal vulnerability to HI. Interestingly, while LPS pre-sensitisation negates the neuroprotective effect of HT, HT is highly beneficial after PAM-sensitised HI brain injury. Objective: We aimed to examine whether systemic gram-positive or gram-negative inflammatory sensitisation affects juvenile rat pups per se, without an HI insult. Methods: Neonatal 7-day-old rats (n = 215) received intraperitoneal injections of vehicle (0.9% NaCl), LPS (0.1 mg/kg), or PAM (1 mg/kg). Core temperature and weight gain were monitored. Brain cytokine expression (IL-6, IL-1β, TNF-α, and IL-10, via PCR), apoptosis (cleaved caspase 3, via Western blots), and microglial activation (Iba1, via immunohistochemistry) were examined. Results: LPS induced an immediate drop in core temperature followed by poor weight gain, none of which were seen after PAM. Furthermore, LPS induced brain apoptosis, while PAM did not. The magnitude and temporal profile of brain cytokine expression differed between LPS- and PAM-injected animals. Conclusion: These findings reveal sepsis-like conditions and neuroinflammation specific to the inflammatory stimulus (gram-positive vs. gram-negative) in the neonatal rat. They emphasise the importance of pre-clinical models being pathogen dependent, and should always be carefully tailored to their clinical scenario.
Expanded Haemodialysis Therapy of Chronic Haemodialysis Patients Prevents Calcification and Apoptosis of Vascular Smooth Muscle Cells in vitro
Authors: Willy Kevin , Girndt Matthias , Voelkl Jakob , Fiedler Roman , Martus Peter , Storr Markus , Schindler Ralf , Zickler Daniel
Published: December 2017

Background: Vascular calcification is a common phenomenon in patients with chronic kidney disease and strongly associated with increased cardiovascular mortality. Vascular calcification is an active process mediated in part by inflammatory processes in vascular smooth muscle cells (VSMC). These could be modified by the insufficient removal of proinflammatory cytokines through conventional high-flux (HF) membranes. Recent trials demonstrated a reduction of inflammation in VSMC by use of dialysis membranes with a higher and steeper cut-off. These membranes caused significant albumin loss. Therefore, the effect of high retention Onset (HRO) dialysis membranes on vascular calcification and its implications in vitro was evaluated. Methods: In the PERCI II trial, 48 chronic dialysis patients were dialyzed using HF and HRO dialyzers and serum samples were collected. Calcifying VSMC were incubated with the serum samples. Calcification was determined using alizarin red staining (AZR) and determination of alkaline phosphatase (ALP) activity. Furthermore, apoptosis was evaluated, and release of matrix Gla protein (MGP), osteopontin (OPN) and growth differentiation factor 15 (GDF-15) were measured in cell supernatants. Results: Vascular calcification in vitro was significantly reduced by 24% (ALP) and 36% (AZR) after 4 weeks of HRO dialysis and by 33% (ALP) and 48% (AZR) after 12 weeks of dialysis using HRO membranes compared to HF dialysis. Apoptosis was significantly lower in the HRO group. The concentrations of MGP and OPN were significantly elevated after incubation with HF serum compared to HRO serum and healthy controls. Similarly, GDF-15 release in the supernatant was elevated after incubation with HF serum, an effect significantly ameliorated after treatment with HRO medium. Conclusions: Expanded haemodialysis therapy reduces the pro-calcific potential of serum from dialysis patients in vitro. With a markedly reduced albumin filtration compared to high cut-off dialysis, use of the HRO dialyzers may possibly provide a treatment option for chronic dialysis patients to reduce the progression of vascular calcification.
Opium Addiction and Ischemic Stroke in Isfahan, Iran: A Case-Control Study
Authors: Ebrahimi Homa , Haghjoo Javanmard Shaghayegh , Asgary Sedigheh , Dehghani Leila , Amiri Masoud , Saadatnia Mohammad
Published: December 2017

Background: The effect of opium addiction (OA) on cerebrovascular disease is controversial. The aim of this study was to clarify this relationship in Iranian patients with ischemic stroke. Methods: In a case-control study, 672 patients with ischemic stroke and 293 controls without a previous history of cerebrovascular or cardiovascular diseases were compared. OA as well as other risk factors such as diabetes mellitus (DM), hypertension (HTN), hyperlipidemia, tobacco smoking (TS) were compared between the 2 groups. Results: OA percentage, TS, TS amount (pack/year), HTN and DM history were significantly higher in the case group compared to controls (p < 0.05). After regression analysis between risk factors, a significant difference remained between 2 groups with regards to HTN (OR 4.21, 95% CI 3.05–5.81, p < 0.001), TS (OR 2.33, 95% CI 1.51–3.59, p < 0.001), and OA (OR 2.36, 95% CI 1.16–4.85, p = 0.018). Conclusion: Our study showed OA is a risk factor for stroke. However, a follow-up study with a larger cohort is required to confirm the results.
Hypertensive Cerebral Hemorrhage in a Patient with Turner Syndrome Caused by Deletion in the Short Arm of the X Chromosome
Authors: Hori Yusuke S. , Ohkura Takahiro , Ebisudani Yuki , Umakoshi Michiari , Ishi Masato , Oda Kazunori , Aoi Mizuho , Inoue Takushi , Furujo Mahoko , Tanaka Hiroyuki , Fukuhara Toru
Published: December 2017

Turner syndrome is a chromosomal disorder usually caused by complete deletion of an X chromosome, with deletion in the short arm of the X chromosome being a rare cause of the condition. Patients with Turner syndrome commonly develop hypertension, and associated vascular complications such as aortic dissection or cerebral hemorrhage have been reported. Cerebral hemorrhage in Turner syndrome is a rare complication, and only a few reports have been published. In these reports, all patients have XO karyotypes or a mosaic type as the cause of Turner syndrome, while no other Turner syndrome types have been documented. In this report, we present for the first time a patient with Turner syndrome caused by deletion in the short arm of the X chromosome who experienced hypertensive hemorrhage as a late complication.
Context Socio-Cultural Of The University In Extension Activities : The Partnership Cefet-Criaad.
Authors: Batista Edvar Fernandes , Mello André Queiroz Ferreira de
Published: December 2017

Considerando a inserção do CEFET/RJ-Nova Friburgo em uma área que abrange outras sete instituições de ensino, formando um verdadeiro polo irradiador da educação, com amplo potencial para colocar em prática a diretriz do Plano Nacional de Educação (PNE), consistente na superação das desigualdades educacionais, com ênfase na promoção da cidadania e na erradicação de todas as formas de discriminação, o presente projeto define seu escopo na oferta de parceria com o Centro de Recursos de Atendimento ao Adolescente (CRIAAD), no sentido de abastecer seu programa pedagógico, com conteúdos que estimulem nos alunos a formação do pensamento crítico, na direção de um aprendizado voltado para o reconhecimento da cidadania como valor universal do ser humano. Nesse contexto, o CEFET/RJ- Nova Friburgo apresenta contribuição através de uma grade de disciplinas voltadas para dois grupos denominados Saberes e Competências. Através do estudo da cidadania e cultura de Nova Friburgo e região, os alunos serão capacitados como Condutores de Visitantes.
Multiescalas de análise urbana para sistemas cicloviários
Authors: Lanziotti Thiago Maioli , Silva André Souza
Published: December 2017

A proposição de sistemas de mobilidade para bicicletas tornou-se foco nos últimos anos devido aos problemas de deslocamento apresentados nas grandes cidades. A presente pesquisa explora métodos de avaliação do espaço urbano em diferentes escalas, a fim de verificar a aplicabilidade conjunta de tais metodologias com o intuito de embasar a leitura mais eficaz do espaço urbano, servindo de subsídio ao planejador urbano na proposição de estruturas destinadas aos modais não-motorizados, em específico o sistema cicloviário. Buscou-se avaliar quais metodologias, qualitativas e quantitativas, aplicadas em conjunto, podem subsidiar o planejamento do transporte por bicicleta. A aplicação da metodologia multiescalas serve de subsídio para a definição de áreas a serem avaliadas, em que o recorte inicia-se na escala de cidade e finaliza na escala local, passando pela escala de bairro. A leitura do espaço urbano utilizando diversas escalas possibilita melhor compreensão da área urbana como um todo e os aspectos que induzem as pessoas a utilizarem os modais não-motorizados, principalmente a bicicleta.
Revisão de Textos Traduzidos: uma experiência na formação de tradutores de português-espanhol
Authors: Bevilacqua Cleci Regina
Published: December 2017

O objetivo deste artigo é oferecer um panorama da disciplina de Revisão de Textos Traduzidos Espanhol/Português no contexto de formação de tradutores em um curso de nível universitário. Busca-se apresentar a relação da disciplina com as competências e habilidades propostas no projeto pedagógico do curso, sua inserção no currículo e seus conteúdos programáticos. Do mesmo modo e com base na proposta de Parra Galiano (2005, 2007), elencam-se, de forma sintetizada, os princípios e parâmetros que orientam as atividades práticas de revisão desenvolvidas no curso. Espera-se poder mostrar a necessidade de uma formação mínima em revisão de textos traduzidos para os futuros profissionais da tradução e motivá-los a serem não apenas revisores de seus próprios textos, mas também de textos de outros profissionais da área. Assim, sua atuação estaria, por um lado, garantindo uma maior qualidade na tradução final e, por outro, abrindo uma possibilidade de inserção em um processo maior, o de edição e publicação de traduções.