Contraction-by-contraction V̇o2 and computer-controlled pump perfusion as novel techniques to study skeletal muscle metabolism in situ

2010 ◽  
Vol 108 (3) ◽  
pp. 705-712 ◽  
Author(s):  
Andrés Hernández ◽  
Matthew L. Goodwin ◽  
Nicola Lai ◽  
Marco E. Cabrera ◽  
James R. McDonald ◽  
...  
Keyword(s):  
Blood Flow ◽  
Moving Average ◽  
Computer Software ◽  
Muscle Metabolism ◽  
New Techniques ◽  
Muscle Oxygen ◽  
Flow Adjustment ◽  
Train Duration ◽  
Muscle Complex

The purpose of this research was to develop new techniques to 1) rapidly sample venous O2 saturation to determine contraction-by-contraction oxygen uptake (V̇o2), and 2) precisely control the rate and pattern of blood flow adjustment from one chosen steady state to another. An indwelling inline oximeter probe connected to an Oximetrix 3 meter was used to sample venous oxygen concentration ([O2]) (via fractional saturation of Hb with O2). Data from the Oximetrix 3 were filtered, deconvolved, and processed by a moving average second by second. Computer software and a program written in-house were used to control blood flow with a peristaltic pump. The isolated canine gastrocnemius muscle complex (GS) in situ was utilized to test these techniques. A step change in metabolic rate was elicited by stimulating GS muscles via their sciatic nerves (supramaximal voltage, 8 V; 50 Hz, 0.2-ms pulse width; train duration 200 ms) at a rate of either 1 contraction/2 s, or 2 contractions/3 s. With arterial [O2] maintained constant, blood flow and calculated venous [O2] were averaged over each contraction cycle and used in the Fick equation to calculate contraction-by-contraction V̇o2. About 5–8 times more data points were obtained with this method compared with traditional manual sampling. Software-controlled pump perfusion enabled the ability to mimic spontaneous blood flow on-kinetics (τ: 14.3 s) as well as dramatically speed (τ: 2.0 s) and slow (τ: 63.3 s) on-kinetics. These new techniques significantly improve on existing methods for mechanistically altering blood flow kinetics as well as accurately measuring muscle oxygen consumption kinetics during transitions between metabolic rates.

Blood flow and muscle metabolism in chronic fatigue syndrome

2003 ◽  
Vol 104 (6) ◽  
pp. 641-647 ◽  
Author(s):  
Kevin K. McCULLY ◽  
Sinclair SMITH ◽  
Sheeva RAJAEI ◽  
John S. LEIGH ◽  
Benjamin H. NATELSON
Keyword(s):  
Blood Flow ◽  
Chronic Fatigue Syndrome ◽  
Muscle Blood Flow ◽  
Muscle Metabolism ◽  
Chronic Fatigue ◽  
Medial Gastrocnemius ◽  
Resonance Spectroscopy ◽  
Muscle Oxygen ◽  
Fatigue Syndrome ◽  
Rate Of Recovery

The purpose of this study was to determine if chronic fatigue syndrome (CFS) is associated with reduced blood flow and oxidative delivery to skeletal muscle. Patients with CFS according to CDC (Center for Disease Control) criteria (n=19) were compared with normal sedentary subjects (n=11). Muscle blood flow was measured with Doppler ultrasound after cuff ischaemia and exercise. Muscle oxygen delivery was measured as the rate of post-exercise and post-ischaemic oxygen-haem resaturation. Oxygen-haem resaturation was measured in the medial gastrocnemius muscle using continuous wavelength near-IR spectroscopy. Muscle metabolism was measured using 31P magnetic resonance spectroscopy. CFS patients and controls were not different in the peak blood flow after cuff ischaemia, the rate of recovery of phosphocreatine after submaximal exercise, and the rate of recovery of oxygen saturation after cuff ischaemia. In conclusion, CFS patients showed no deficit in blood flow or oxidative metabolism. This suggests that CFS symptoms do not require abnormal peripheral function.

Direct Assessment of Glomerular Arteriole Reactivity

Physiology ◽  
1988 ◽  
Vol 3 (5) ◽  
pp. 216-219
Author(s):  
RM Edwards
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
New Techniques ◽  
Direct Assessment ◽  
Renal Microvasculature ◽  
Glomerular Arterioles

The glomerular arterioles play an important role in the regulation of renal blood flow and glomerular filtration rate. The need to understand how glomerular arteriole resistance is regulated has led to the development of new techniques to directly study these important segments of the renal microvasculature in vitro and in situ.

Blood flow from and oxygen uptake by muscle, during and after partial venous occlusion

1962 ◽  
Vol 203 (3) ◽  
pp. 470-474 ◽  
Author(s):  
John T. Fales ◽  
S. Richard Heisey ◽  
Kenneth L. Zierler
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Arterial Occlusion ◽  
Venous Occlusion ◽  
Oxygen Debt ◽  
Muscle Oxygen ◽  
Muscle Oxygen Consumption ◽  
Passive Stretch ◽  
Oxygen Difference

In dog gastrocnemius-plantaris muscle in situ, effects of partial venous occlusion and its release were compared to effects of arterial occlusion and release. During partial venous occlusion, blood flow decreases, arteriovenous oxygen difference is constant, and oxygen consumption is, therefore, reduced proportionately to blood flow. On release of partial venous occlusion, unlike release of arterial occlusion in which both blood flow debt and oxygen debt are repaid, there is little or no repayment of blood flow debt, arteriovenous oxygen difference remains constant, and there is, therefore, little or no repayment of oxygen debt. These effects of partial venous occlusion are reminiscent of those reported to occur during and after release of passive stretch of circulated muscle, and it is proposed that the stretch effect is secondary to venular occlusion. The observations are consistent with the hypothesis that, within limits, muscle oxygen consumption is dependent on or limited by blood flow.

V̇o2 on-kinetics in isolated canine muscle in situ during slowed convective O2 delivery

2012 ◽  
Vol 112 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Matthew L. Goodwin ◽  
Andrés Hernández ◽  
Nicola Lai ◽  
Marco E. Cabrera ◽  
L. Bruce Gladden
Keyword(s):  
Blood Flow ◽  
Steady State ◽  
Near Infrared ◽  
Transition Period ◽  
Blood Flows ◽  
Mean Response Time ◽  
Experimental Trial ◽  
Muscle Complex ◽  
Anesthetized Dogs

The purpose of this study was to examine O2 uptake (V̇o2) on-kinetics when the spontaneous blood flow (and therefore O2 delivery) on-response was slowed by 25 and 50 s. The isolated gastrocnemius muscle complex (GS) in situ was studied in six anesthetized dogs during transitions from rest to a submaximal metabolic rate (≈50–70% of peak V̇o2). Four trials were performed: 1) a pretrial in which resting and steady-state blood flows were established, 2) a control trial in which the blood flow on-kinetics mean response time (MRT) was set at 20 s (CT20), 3) an experimental trial in which the blood flow on-kinetics MRT was set at 45 s (EX45), and 4) an experimental trial in which the blood flow on-kinetics MRT was set at 70 s (EX70). Slowing O2 delivery via slowing blood flow on-kinetics resulted in a linear slowing of the V̇o2 on-kinetics response ( R = 0.96). Average MRT values for CT20, EX45, and EX70 V̇o2 on-kinetics were (means ± SD) 17 ± 2, 23 ± 4, and 26 ± 3 s, respectively ( P < 0.05 among all). During these transitions, slowing blood flow resulted in greater muscle deoxygenation (as indicated by near-infrared spectroscopy), suggesting that lower intracellular Po2 values were reached. In this oxidative muscle, V̇o2 and O2 delivery were closely matched during the transition period from rest to steady-state contractions. In conjunction with our previous work showing that speeding O2 delivery did not alter V̇o2 on-kinetics under similar conditions, it appears that spontaneously perfused skeletal muscle operates at the nexus of sufficient and insufficient O2 delivery in the transition from rest to contractions.

Muscle maximal O2 uptake at constant O2 delivery with and without CO in the blood

1990 ◽  
Vol 69 (3) ◽  
pp. 830-836 ◽  
Author(s):  
M. C. Hogan ◽  
D. E. Bebout ◽  
A. T. Gray ◽  
P. D. Wagner ◽  
J. B. West ◽  
...  
Keyword(s):  
Blood Flow ◽  
Muscle Blood Flow ◽  
Hemoglobin Concentration ◽  
O2 Uptake ◽  
Isometric Twitch ◽  
O2 Delivery ◽  
Arterial Po2 ◽  
O2 Dissociation Curve ◽  
Total Hemoglobin Concentration

In the present study we investigated the effects of carboxyhemoglobinemia (HbCO) on muscle maximal O2 uptake (VO2max) during hypoxia. O2 uptake (VO2) was measured in isolated in situ canine gastrocnemius (n = 12) working maximally (isometric twitch contractions at 5 Hz for 3 min). The muscles were pump perfused at identical blood flow, arterial PO2 (PaO2) and total hemoglobin concentration [( Hb]) with blood containing either 1% (control) or 30% HbCO. In both conditions PaO2 was set at 30 Torr, which produced the same arterial O2 contents, and muscle blood flow was set at 120 ml.100 g-1.min-1, so that O2 delivery in both conditions was the same. To minimize CO diffusion into the tissues, perfusion with HbCO-containing blood was limited to the time of the contraction period. VO2max was 8.8 +/- 0.6 (SE) ml.min-1.100 g-1 (n = 12) with hypoxemia alone and was reduced by 26% to 6.5 +/- 0.4 ml.min-1.100 g-1 when HbCO was present (n = 12; P less than 0.01). In both cases, mean muscle effluent venous PO2 (PVO2) was the same (16 +/- 1 Torr). Because PaO2 and PVO2 were the same for both conditions, the mean capillary PO2 (estimate of mean O2 driving pressure) was probably not much different for the two conditions, even though the O2 dissociation curve was shifted to the left by HbCO. Consequently the blood-to-mitochondria O2 diffusive conductance was likely reduced by HbCO.(ABSTRACT TRUNCATED AT 250 WORDS)

Hybrid MPI-MRI System for Dual-Modal In Situ Cardiovascular Assessments of Real-Time 3D Blood Flow Quantification—A Pre-Clinical In Vivo Feasibility Investigation

2020 ◽  
Vol 39 (12) ◽  
pp. 4335-4345
Author(s):  
Jochen Franke ◽  
Nicoleta Baxan ◽  
Heinrich Lehr ◽  
Ulrich Heinen ◽  
Sebastian Reinartz ◽  
...  
Keyword(s):  
Blood Flow ◽  
Real Time ◽  
Flow Quantification ◽  
Blood Flow Quantification

scholarly journals Intermittent pneumatic leg compressions enhance muscle performance and blood flow in a model of peripheral arterial insufficiency

2012 ◽  
Vol 112 (9) ◽  
pp. 1556-1563 ◽  
Author(s):  
Bruno T. Roseguini ◽  
Arturo A. Arce-Esquivel ◽  
Sean C. Newcomer ◽  
Hsiao T. Yang ◽  
Ronald Terjung ◽  
...  
Keyword(s):  
Blood Flow ◽  
Exercise Tolerance ◽  
Citrate Synthase ◽  
Arterial Disease ◽  
Muscle Performance ◽  
Sprague Dawley ◽  
Arterial Insufficiency ◽  
Mechanistic Basis ◽  
Peripheral Arterial

Despite the escalating prevalence in the aging population, few therapeutic options exist to treat patients with peripheral arterial disease. Application of intermittent pneumatic leg compressions (IPC) is regarded as a promising noninvasive approach to treat this condition, but the clinical efficacy, as well the mechanistic basis of action of this therapy, remain poorly defined. We tested the hypothesis that 2 wk of daily application of IPC enhances exercise tolerance by improving blood flow and promoting angiogenesis in skeletal muscle in a model of peripheral arterial insufficiency. Male Sprague-Dawley rats were subjected to bilateral ligation of the femoral artery and randomly allocated to treatment or sham groups. Animals were anesthetized daily and exposed to 1-h sessions of bilateral IPC or sham treatment for 14–16 consecutive days. A third group of nonligated rats was also studied. Marked increases in treadmill exercise tolerance (∼33%, P < 0.05) and improved muscle performance in situ (∼10%, P < 0.05) were observed in IPC-treated animals. Compared with sham-treated controls, blood flow measured with isotope-labeled microspheres during in situ contractions tended to be higher in IPC-treated animals in muscles composed of predominantly fast-twitch white fibers, such as the plantaris (∼93%, P = 0.02). Capillary contacts per fiber and citrate synthase activity were not significantly altered by IPC treatment. Collectively, these data indicate that IPC improves exercise tolerance in a model of peripheral arterial insufficiency in part by enhancing blood flow to collateral-dependent tissues.

Study on Coordination of Heterogeneous Databases

2014 ◽  
Vol 608-609 ◽  
pp. 336-342
Author(s):  
Huan Liu
Keyword(s):  
Hot Spot ◽  
Computer Software ◽  
Heterogeneous Databases ◽  
Important Research ◽  
Heterogeneous Database ◽  
New Techniques ◽  
Directory Service ◽  
New Development ◽  
Development Direction ◽  
New Applications

How to coordinate heterogeneous database to realize sharing and consistency of information not only is an important research subject in the database filed, but also is an emerging research hot spot in the field of database system. As a new development direction of computer software, it applies some new techniques to integrate the existing systems to develop new applications. The paper analyzes CSCW, XML, JDBC and heterogeneous database, and proposes a solution of heterogeneous database. The solution absorbs the thoughts of database meta data, middle ware and LDAP directory service.

Increased muscle fatigability in GLUT-4-deficient mice

2002 ◽  
Vol 282 (2) ◽  
pp. E348-E354 ◽  
Author(s):  
M. Gorselink ◽  
M. R. Drost ◽  
K. F. J. de Brouwer ◽  
G. Schaart ◽  
G. P. J. van Kranenburg ◽  
...  
Keyword(s):  
Peak Power ◽  
Fiber Type ◽  
Flexor Muscle ◽  
Glut 4 ◽  
Muscle Complex ◽  
Alternative Routes ◽  
Deficient Mice ◽  
Shortening Contractions ◽  
Contractile Performance

GLUT-4 plays a predominant role in glucose uptake during muscle contraction. In the present study, we have investigated in mice whether disruption of the GLUT-4 gene affects isometric and shortening contractile performance of the dorsal flexor muscle complex in situ. Moreover, we have explored the hypothesis that lack of GLUT-4 enhances muscle fatigability. Isometric performance normalized to muscle mass during a single tetanic contraction did not differ between wild-type (WT) and GLUT-4-deficient [GLUT-4(−/−)] mice. Shortening contractions, however, revealed a significant 1.4-fold decrease in peak power per unit mass, most likely caused by the fiber-type transition from fast-glycolytic fibers (IIB) to fast-oxidative fibers (IIA) in GLUT-4(−/−) dorsal flexors. In addition, the resting glycogen content was significantly lower (34%) in the dorsal flexor complex of GLUT-4(−/−) mice than in WT mice. Moreover, the muscle complex of GLUT-4(−/−) mice showed enhanced susceptibility to fatigue, which may be related to the decline in the muscle carbohydrate store. The significant decrease in relative work output during the steady-state phase of the fatigue protocol suggests that energy supply via alternative routes is not capable to compensate fully for the lack of GLUT-4.

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