Augmented upper body contribution to oxygen uptake during upper body exercise with concurrent leg functional electrical stimulation in persons with spinal cord injury

The purpose of this pilot study was to compare the contribution of upper body musculature to VO2 with and without concurrent leg FES (LFES). Eight subjects with spinal cord injury, lesion levels range C6-T12, performed upper body exercise (UBE) during no LFES (NOS), LFES at 40 mA (LOS), and 80 mA (HIS), at rest, 60% and 80% of VO2peak. Resting VO2 values were obtained during NOS, LOS and HIS conditions and were then subtracted from their respective whole body VO2 values to give an estimate of upper body VO2. Small and non significant increases were found in the HIS vs NOS condition at 60% VO2peak. Larger differences of 7.8% were found in the HIS vs NOS condition at 80% VO2peak (11.35+/-3.8 ml kg(-1) min(-1) to 12.24+/-4.0 ml kg(-1) min(-1)), although this too was not significant, perhaps due to the small number of subjects in this study and the consequently low statistical power to detect a significant difference. We discuss the implications for these preliminary results in the context of the existing literature on this topic.     

A dynamic model of the hand with application in functional neuromuscular stimulation

Potential hand function in people with tetraplegia was evaluated using a three-dimensional dynamic mathematical model. The model was used to evaluate hand positioning, grasp force, and the outcome of surgeries such as tendon transfers and joint fusion, in situations typical of those encountered when using functional neuromuscular stimulation to restore function in people with tetraplegia. In the model, the hand is treated as a jointed multibody system. Each joint is subjected to muscle moments, passive joint moment, and moments due to grasp forces. Model simulations showed that function was highly dependent on both muscle strength and joint passive moments. The potential for tendon transfers, such as the Zancolli-lasso and intrinsicplasty, plasty, to improve hand function was demonstrated, but their value is subject-dependent. It was also shown that activation of multiple thumb muscles (adductor pollicis, abductor pollicis brevis, and flexor pollicis longus) without interphalangeal joint fusion can provide convenient lateral pinch posture with approximately 70% more grip force than a currently used method, which includes joint fusion but requires only one muscle. Finally, a grasp protocol was introduced and shown successful in palmar grasp and hold of movable cylindrical objects using only extrinsic muscles, provided the fingers could be extended sufficiently to enclose the object.     

Hippocampal activity, behavior, self-stimulation, and heart rate during electrical stimulation of the lateral hypothalamus.

Observed hippocampal electrical activity in relation to behavior elicited by stimulation of the lateral hypothalamus in 30 male hooded rats. Rhythmical slow activity (RSA) was always present during walking, rearing, digging, bar pressing, and other presumably "voluntary" movements, but at low stimulation intensities it was often absent during licking, chewing, face washing, and other presumably "automatic" movements. At higher stimulation intensities, Ss became hyperactive and RSA was almost continually present. No relation was found between RSA and heart rate or licking movements. An ascending hypothalamic system may require hippocampal participation in the control of voluntary movements, but hippocampal participation may not be required for the control of more automatic movements. (30 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heart rate conditioning in newborn infants: Relationships among conditionability, heart rate variability, and sex.

Evaluated trace conditioning in 20 newborn infants by examining heart rate responses to the conditioned stimulus (CS), in anticipation of the unconditioned stimulus (UCS) and in the absence of the UCS. 2 sets of analyses were performed using subgroups based on preexperimental heart rate variability and sex. Preexperimental heart rate variability was related only to the response to the CS, with only the high-variance Ss showing a conditioned deceleration and exhibiting a change in response across trial blocks. Only the females exhibited conditioned decelerations in response to the CS and in anticipation of the UCS. In the absence of the UCS, only the experimental group as a whole responded with a deceleration. The relationship between sex and heart rate variability was also examined. Data suggest that females tend to have higher levels of heart rate variability which parallels their greater conditionability. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Oxygen uptake kinetics during low level exercise in patients with heart failure: relation to neurohormones, peak oxygen consumption, and clinical findings

OBJECTIVE: To investigate whether oxygen uptake (VO2) kinetics during low intensity exercise are related to clinical signs, symptoms, and neurohumoral activation independently of peak oxygen consumption in chronic heart failure. DESIGN: Comparison of VO2 kinetics with peak VO2, neurohormones, and clinical signs of chronic heart failure. SETTING: Tertiary care centre. PATIENTS: 48 patients with mild to moderate chronic heart failure. INTERVENTIONS: Treadmill exercise testing with "breath by breath" gas exchange monitoring. Measurement of atrial natriuretic factor (ANF), brain natriuretic peptide (BNP), and noradrenaline. Assessment of clinical findings by questionnaire. MAIN OUTCOME MEASURES: O2 kinetics were defined as O2 deficit (time [rest to steady state] x DeltaVO2 -sigmaVO2 [rest to steady state]; normalised to body weight) and mean response time of oxygen consumption (MRT; O2 deficit/DeltaVO2). RESULTS: VO2 kinetics were weakly to moderately correlated to the peak VO2 (O2 deficit, r = -0.37, p < 0.05; MRT, r = -0.49, p < 0.001). Natriuretic peptides were more closely correlated with MRT (ANF, r = 0.58; BNP, r = 0.53, p < 0.001) than with O2 deficit (ANF, r = 0.48, p = 0.001; BNP, r = 0.37, p < 0.01) or peak VO2 (ANF, r = -0.40; BNP, r = -0.31, p < 0.05). Noradrenaline was correlated with MRT (r = 0. 33, p < 0.05) and O2 deficit (r = 0.39, p < 0.01) but not with peak VO2 (r = -0.20, NS). Symptoms of chronic heart failure were correlated with all indices of oxygen consumption (MRT, r = 0.47, p < 0.01; O2 deficit, r = 0.39, p < 0.01; peak VO2, r = -0.48, p < 0. 01). Multivariate analysis showed that the correlation of VO2 kinetics with neurohormones and symptoms of chronic heart failure was independent of peak VO2 and other variables. CONCLUSIONS: Oxygen kinetics during low intensity exercise may provide additional information over peak VO2 in patients with chronic heart failure, given the better correlation with neurohormones which represent an index of homeostasis of the cardiovascular system.     

Changes in maximum oxygen uptake during prolonged training, overtraining, and detraining in horses

Thirteen standardbred horses were trained as follows: phase 1 (endurance training, 7 wk), phase 2 (high-intensity training, 9 wk), phase 3 (overload training, 18 wk), and phase 4 (detraining, 12 wk). In phase 3, the horses were divided into two groups: overload training (OLT) and control (C). The OLT group exercised at greater intensities, frequencies, and durations than group C. Overtraining occurred after 31 wk of training and was defined as a significant decrease in treadmill run time in response to a standardized exercise test. In the OLT group, there was a significant decrease in body weight (P < 0.05). From pretraining values of 117 +/- 2 (SE) ml.kg-1.min-1, maximal O2 uptake (VO2max) increased by 15% at the end of phase 1, and when signs of overtraining were first seen in the OLT group, VO2max was 29% higher (151 +/- 2 ml.kg-1.min-1 in both C and OLT groups) than pretraining values. There was no significant reduction in VO2max until after 6 wk detraining when VO2max was 137 +/- 2 ml.kg-1.min-1. By 12 wk detraining, mean VO2max was 134 +/- 2 ml.kg-1.min-1, still 15% above pretraining values. When overtraining developed, VO2max was not different between C and OLT groups, but maximal values for CO2 production (147 vs. 159 ml.kg-1.min-1) and respiratory exchange ratio (1.04 vs. 1.11) were lower in the OLT group. Overtraining was not associated with a decrease in VO2max and, after prolonged training, decreases in VO2max occurred slowly during detraining.     

Neuromuscular blocking drugs and heart rate changes after direct nerve stimulation and during classical conditioning in cats.

2 experiments investigated cardiovascular responses to several common neuromuscular blocking compounds. Exp I, employing 16 male cats, assessed ganglionic transmission in sympathetic and parasympathetic systems controlling heart rate and blood pressure after dextrotubocurarine chloride (TC), dimethyl dextrotubocurarine iodide (DTI), succinylcholine chloride (SC), or saline. Cardiovascular responses to sympathetic stimulation were essentially unaffected at drug levels that blocked evoked electromyograms; however, vagally evoked bradycardia and corresponding blood pressure decrease were blocked by TC and reduced by DTI and SC. Exp II compared heart responses of 12 male cats under the same blocking compounds during differential classical aversive conditioning. Differential conditioned responses and unconditioned responses occurred under DTI, less under SC, but not under TC. However, Ss trained under TC and tested under DTI showed differential conditioned responses. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Maximal oxygen uptake during exercise with various combinations of arm and leg work

Oxygen uptake (VO2) was determined in 10 males during the following types of maximal exercise (work time: about 5 min): uphill running, bicycling, arm work (cranking), and combined arm work and bicycling (A + L). The A + L exercise was performed in four different ways, the arms doing 10%, 20%, 30%, or 40% of the same total rate of work; and also with the maximal bicycle work load plus either maximal or submaximal arm work. VO2 was the same in running as in all types of A + L exercise, except when the arm work load was 10% and 40% of the total rate of work, where VO2 was 2.5% (P less than 0.05) and 9.4% (P less than 0.001) lower, respectively. Bicycle VO2 was lower than VO2 in running but equal to A + L VO2 when arm work intensity was 40% of the total rate of work. It is concluded that VO2 during maximal exercise a) to a certain extent depends on the exercising muscle mass, b) is lower than the oxygen-consuming potential of the muscles involved in A + L exercise, and c) in A + L exercise is influenced by the ratio of arm work to total rate of work and the subject's fitness for arm work and bicycling.     

Speed dependence of crutch force and oxygen uptake: implications for design of comparative trials on orthoses for people with paraplegia

The major defence mechanism in frogs in via the secretion of toxins from their skin. In humans, intoxication may occur when part of the amphibian integument is ingested, as in the form of herbal medicines. Two groups of South African frogs have skin secretions that are potentially lethal to humans and animals. Toads (Bufo and Schismaderma species), the amphibians with which man and his pets most frequently have contact, secrete potent toxins with cardiac glycoside activity. Topical and systemic intoxication, while seen in humans, remains predominantly a veterinary problem. Intoxication by the red-banded rubber frog, which secretes an unidentified cardiotoxin, is far less common. The probable mechanisms of intoxication and management of a poisoned patient are discussed.     

Determination of heart time volume using the Fick principle in the early postoperative phase after correction of congenital heart defects. Comparison of the calculation of arterio-mixed venous oxygen differences and pulmonary oxygen uptake with the calculation of arterial-central venous oxygen differences and pulmonary oxygen uptake

Comparison of the calculation by means of the arterio-mixed venous oxygen difference and the oxygen uptake with the calculation by means of the arterio-central venous oxygen difference and the oxygen uptake. OBJECTIVE: How reliable is the measurement of cardiac output on Fick's principle without a pulmonary artery catheter? SETTING: PICU in an University hospital. DESIGN: In the postoperative period following complete repair of congenital heart disease we carried out 91 simultaneous measurements of blood gases in 45 infants and children (mean age 18.6 months, mean body weight 8.9 kg) from a systemic artery, the A. pulmonalis, and the V. cava superior. We also determined the pulmonary oxygen uptake in 24 patients (48 measurements). Cardiac output was calculated on Fick's principle using the arterio-mixed venous oxygen difference and the pulmonary oxygen uptake (HZV a-pa) and compared to the cardiac output derived from the central venous values (HZV a-zv). We differentiated between patients with a left to right shunt of 10% or more postoperatively (group A, n = 18) and all others (group B, n = 27). RESULTS: In both groups the correlation coefficient between HZV a-zv and HZV a-pa was high (group A: r = 0.97, group B: r = 0.94). In group A HZV a-pa (mean: 1958 ml/min) was higher than HZV a-zv (mean: 1340 ml/min), group B showed the opposite situation (mean HZV a-pa: 1136 ml/min, mean HZV a-zv: 1373 ml/min). With the Wilcoxon signet-rank test we found significant differences between the partial pressure of oxygen and the saturation of central venous and mixed venous blood samples in both groups, but HZV a-zv and HZV a-pa were different significantly on a level of p < or = 0.01 only in group A. CONCLUSIONS: In both groups HZV a-pa and HZV a-zv correlated well. Therefore, if a pulmonary artery catheter is not inserted; the course of the cardiac output can be calculated with acceptable reliability from the central venous blood gases. By means of Fick's principle the pulmonary blood flow is determined, which is higher than the systemic blood flow in cases of left to right shunting, because of the recirculation in the pulmonary blood circuit. Interpreting the results this has to be taken into account.     

Evaluation of the cardiac and pulmonary uptake of Thallium 201 in subject with suspected ischemic heart disease examined by single-photon emission tomography with Thallium 201, at rest and after exertion

Counts in selected lung and heart ROI were taken in 10 thallium-201 stress SPECT. They were tested for diseased or welfare status of the patient. Eighteen parameters from scintigraphies and from stress test for each patient were placed in a file and tested for correlation in a minicomputer. Lung/heart ratio was found to be not indicative of disease while it is a sign of thallium distribution in the body. Numerical evaluation of scintigraphies was however found to be a sign of disease.     

Scaling of submaximal oxygen uptake with body mass and combined mass during uphill treadmill bicycling

This study examined the scaling relationships of net O2 uptake [V(O2)(net) = V(O2) - resting V(O2)] to body mass (MB) and combined mass (MC = MB + bicycle) during uphill treadmill bicycling. It was hypothesized that V(O2)(net) (l/min) would scale proportionally with MC [i.e., VO2(net) approximately M1.0C] and less than proportionally with MB [i.e., V(O2)(net) approximately MB]. Twenty-five competitive cyclists [73.9 +/- 8.8 and 85.0 +/- 9.0 (SD) kg for MB and MC, respectively] rode their bicycles on a treadmill at 3.46 m/s and grades of 1.7, 3.5, 5.2, and 7.0% while V(O2) was measured. Multiple log-linear regression procedures were applied to the pooled V(O2)(net) data to determine the exponents for MC and MB after statistically controlling for differences in treadmill grade and dynamic friction. The regression models were highly significant (R2 = 0.95, P < 0.001). Exponents for MC (0.99, 95% confidence interval = 0.80-1.18) and MB (0.89, 95% confidence interval = 0.72-1. 07) did not differ significantly from each other or 1.0. It was concluded that the 0.99 MC exponent was due to gravitational resistance, whereas the MB exponent was <1.0 because the bicycles were relatively lighter for heavier cyclists.     

Reactivity of skin blood flow and heart rate to external thermal stimulation in anencephaly

Stromal endometriosis refers to the presence of endometriotic stroma without the presence of endometrial glands. We report a case in the uterine cervix in which the diagnosis of Kaposi's sarcoma was considered before being discounted on histological and immunohistochemical grounds.     

The effects of electrical stimulation of the nucleus basalis on the electroencephalogram, heart rate, and respiration.

The nucleus basalis (NB) mediates cortical electroencephalograph (EEG) activation; NB stimulation also modulates cortical responses to sensory stimuli and can induce learning-related receptive field plasticity. However, little is known about the behavioral effects of NB stimulation. This study concerns the effects of NB stimulation on cardiac and respiratory behavior and quantifies its EEG effects in freely moving rats. The EEG exhibited stimulation-induced decreases in theta and alpha power and increases in gamma power. NB stimulation elicited biphasic heart rate changes and disrupted ongoing respiration patterns. Neither EEG nor behavioral effects exhibited habituation or facilitation. These results indicate that the NB may serve not only as a cortical, but also as a behavioral, activation system that is normally engaged during learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavior of the lipid and carbohydrate metabolism in patients with hypertriglyceridemia during exertion

In pateints with hypertriglyceridaemia in rest and during ergometer load an increased rate of lipolysis with increased metabolism of free fatty acids could be proved. This led to a disturbance of the glucose tolerance with hyperinsulinism and during muscle work to a limitation of the capacity of the oxidative glucose metabolism in musculature.     

Ankle, knee, and hip moments during standing with and without joint contractures: simulation study for functional electrical stimulation

Joint contractures have been one of the contraindications for use of functional electrical stimulation for standing in paraplegic patients. A simulation study using a three-segment link mechanical model of the human body was performed to calculate the muscle moments at the ankles, knees, and hips during standing with and without having joint contractures. The knee and hip angles were varied in 5 degrees increments, whereas the ankle angles were varied in 1 degree increments. It was assumed that energy efficient posture was obtained with the least sum of the squared moments of the ankles, knees, and hips joints by the muscles. Ankles at 5 degrees of dorsiflexion, knees at 0 degrees, and hips at 15 degrees of extension resulted in the most energy efficient posture without joint contractures. The muscle moments increased with the increase in angle of contractures. The joint contractures at ankle angles > or = 6 degrees of plantar flexion, knee angles > or = 20 degrees of flexion, and/or hip angles > or = 20 degrees of flexion produce a potentially unstable posture. These findings suggest that some degree of joint contractures can be tolerated in paraplegic patients using functional electrical stimulation for standing.     

Blood pressure, renin activity and heart rate changes during propranolol therapy of hypertension

Seven boys with fracture(s) of the bony pelvis and associated partial or complete rupture of the posterior urethra were managed by the time-honored technique of early suprapubic cystostomy and concomitant primary realignment of the urethra over a catheter. Of the 4 children who had a functionally significant urethral stricture 3 were cured within a few months by 1 or 2 simple urethral dilatations and 1 by subsequent transperineal lysis of the angulated urethra from its surrounding fibrous tissue. Followup data for 8 to 22 years (mean 14 years) indicate that all 7 patients void with an excellent stream and are continent, free of infection and potent. In fact, 3 of the 4 married boys have fathered children.