Effect of O2 breathing on pulmonary compliance

1962 ◽  
Vol 17 (2) ◽  
pp. 233-238 ◽  
Author(s):  
Zora J. Griffo ◽  
Albert Roos
Keyword(s):  
Atmospheric Pressure ◽  
Human Subjects ◽  
Normal Subjects ◽  
Pure Oxygen ◽  
Pulmonary Atelectasis ◽  
Air Breathing ◽  
Oxygen Breathing ◽  
Pulmonary Compliance ◽  
Effect Of Oxygen

The effect of oxygen breathing on pulmonary compliance was studied in paralyzed, artificially ventilated dogs and in two normal subjects. 1) In the dogs and the human subjects the course of compliance during oxygen breathing for periods of 1frac12–2 hr following hyperinflation was compared with that during air breathing. 2) In dogs compliance after apnea on oxygen (following hyperinflation) for frac12–7 min was compared with that after apnea on air. Intrapulmonary pressure during apnea was atmospheric. 3) In the human subjects the course of compliance was followed during air breathing for 50–70 min, preceded by hyperinflation and immediately followed by oxygen breathing for 80–100 min. In none of these three sets of studies did oxygen breathing affect the course or magnitude of pulmonary compliance. It is concluded that breathing pure oxygen at atmospheric pressure for several hours does not enhance the development of pulmonary atelectasis in normal subjects. Submitted on July 3, 1961

Effect of oxygen breathing at atmospheric pressure on pulmonary surfactant

1965 ◽  
Vol 20 (5) ◽  
pp. 855-858 ◽  
Author(s):  
Samuel T. Giammona ◽  
Donald Kerner ◽  
Stuart Bondurant
Keyword(s):  
Surface Tension ◽  
Atmospheric Pressure ◽  
Pulmonary Surfactant ◽  
Species Difference ◽  
Foam Fractionation ◽  
Minimum Surface ◽  
Oxygen Breathing ◽  
Minimum Surface Tension ◽  
Effect Of Oxygen

To evaluate the effects of oxygen breathing at atmospheric pressure on pulmonary surfactant, cats, rabbits, and rats were continuously kept in 98% oxygen until death occurred. Pulmonary surfactant was extracted by mincing of the lung and by foam fractionation of the lung. Surface tension of the extracts was measured on a Wilhelmy balance. Lung extracts prepared by both methods from the cats and rabbits kept in oxygen had greater surface tension than lung extracts from control animals. Surface tension of extracts prepared by foam fractionation of lungs of rats kept in oxygen did not differ from that of extracts of lungs of control rats, whereas surface tension of extracts prepared by mincing lungs of rats kept in oxygen had minimum surface tension greater than that of lung extracts of control rats. This species difference in the effects of oxygen breathing on pulmonary surfactant may reflect a difference in the pathogenesis of oxygen intoxication. oxygen intoxication; surface tension Submitted on October 19, 1964

EFFECT OF OXYGEN BREATHING AT ATMOSPHERIC PRESSURE ON PULMONARY SURFACTANT

1966 ◽  
Vol 10 (5) ◽  
pp. 417
Author(s):  
S. T. GIAMMONA ◽  
D. KERNER ◽  
S. BONDURANT ◽  
MEYER SAKLAD
Keyword(s):  
Atmospheric Pressure ◽  
Pulmonary Surfactant ◽  
Oxygen Breathing ◽  
Effect Of Oxygen

Effects of galvanic mastoid stimulation in seated human subjects

2009 ◽  
Vol 106 (3) ◽  
pp. 893-903 ◽  
Author(s):  
Z. Ghanim ◽  
J. C. Lamy ◽  
A. Lackmy ◽  
V. Achache ◽  
N. Roche ◽  
...  
Keyword(s):  
Human Subjects ◽  
Normal Subjects ◽  
Standing Position ◽  
Reflex Response ◽  
Emg Activity ◽  
Free Standing ◽  
Vestibular Response ◽  
Vestibular Reflex ◽  
Tendon Jerk ◽  
Biphasic Responses

The vestibular responses evoked by transmastoid galvanic stimulation (GS) in the rectified soleus electromyogram (EMG) in freely standing human subjects disappear when seated. However, a GS-induced facilitation of the soleus monosynaptic (H and tendon jerk) reflex has been described in few experiments in subjects lying prone or seated. This study addresses the issue of whether this reflex facilitation while seated is of vestibulospinal origin. GS-induced responses in the soleus (modulation of the rectified ongoing EMG and of the monosynaptic reflexes) were compared in the same normal subjects while freely standing and sitting with back and head support. The polarity-dependent biphasic responses in the free-standing position were replaced by a non-polarity-dependent twofold facilitation while seated. The effects of GS were hardly detectable in the rectified ongoing voluntary EMG activity, weak for the H reflex, but large and constant for the tendon jerk. They were subject to habituation. Anesthesia of the skin beneath the GS electrodes markedly reduced the reflex facilitation, while a similar, although weaker, facilitation of the tendon jerk was observed when GS was replaced with purely cutaneous stimulation, a tap to the tendon of the sternomastoid muscle, or an auditory click. The stimulation polarity independence of the GS-induced reflex facilitation argues strongly against a vestibular response. However, the vestibular afferent volley, insufficient to produce a vestibular reflex response while seated, could summate with the GS-induced tactile or proprioceptive volley to produce a startle-like response responsible for the reflex facilitation.

scholarly journals Reproducibility of Cerebral Glucose Metabolic Measurements in Resting Human Subjects

1988 ◽  
Vol 8 (4) ◽  
pp. 502-512 ◽  
Author(s):  
Elsa J. Bartlett ◽  
Jonathan D. Brodie ◽  
Alfred P. Wolf ◽  
David R. Christman ◽  
Eugene Laska ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Brain Metabolism ◽  
Human Subjects ◽  
Normal Subjects ◽  
Time Of Day ◽  
Cerebral Glucose Metabolism ◽  
Whole Brain ◽  
Positron Emission ◽  
Subcortical Regions ◽  
Regional Cerebral Glucose Metabolism

Positron emission tomography with 11C-2-deoxyglucose was used to determine the test-retest variability of regional cerebral glucose metabolism in 22 young normal right-handed men scanned twice in a 24-h period under baseline (resting) conditions. To assess the effects of scan order and time of day on variability, 12 subjects were scanned in the morning and afternoon of the same day (a.m.-p.m.) and 10 in the reverse order (p.m.-a.m.) with a night in between. The effect of anxiety on metabolism was also assessed. Seventy-three percent of the total subject group showed changes in whole brain metabolism from the first to the second measurement of 10% or less, with comparable changes in various cortical and subcortical regions. When a scaling factor was used to equate the whole brain metabolism in the two scans for each individual, the resulting average regional changes for each group were no mote than 1%. This suggests that the proportion of the whole brain metabolism utilized regionally is stable in a group of subjects over time. Both groups of subjects had lower morning than afternoon metabolism, but the differences were slight in the p.m.-a.m. group. One measure of anxiety (pulse at fun 1) was correlated with run 1 metabolism and with the percentage of change from run 1 to run 2. No significant run 2 correlations were observed. This is the first study to measure test-retest variability in cerebral glucose metabolism in a large sample of young normal subjects. It demonstrates that the deoxyglucose method yields low Intrasubject variability and high stability over a 24-h period.

Effect of combined recompression and air, oxygen, or heliox breathing on air bubbles in rat tissues

2001 ◽  
Vol 90 (5) ◽  
pp. 1639-1647 ◽  
Author(s):  
O. Hyldegaard ◽  
D. Kerem ◽  
Y. Melamed
Keyword(s):  
Adipose Tissue ◽  
White Matter ◽  
Decompression Sickness ◽  
Rat Tissues ◽  
Air Bubbles ◽  
Transient Growth ◽  
Air Exposure ◽  
Air Breathing ◽  
Oxygen Breathing ◽  
Clinical Observations

The fate of bubbles formed in tissues during the ascent from a real or simulated air dive and subjected to therapeutic recompression has only been indirectly inferred from theoretical modeling and clinical observations. We visually followed the resolution of micro air bubbles injected into adipose tissue, spinal white matter, muscle, and tendon of anesthetized rats recompressed to and held at 284 kPa while rats breathed air, oxygen, heliox 80:20, or heliox 50:50. The rats underwent a prolonged hyperbaric air exposure before bubble injection and recompression. In all tissues, bubbles disappeared faster during breathing of oxygen or heliox mixtures than during air breathing. In some of the experiments, oxygen breathing caused a transient growth of the bubbles. In spinal white matter, heliox 50:50 or oxygen breathing resulted in significantly faster bubble resolution than did heliox 80:20 breathing. In conclusion, air bubbles in lipid and aqueous tissues shrink and disappear faster during recompression during breathing of heliox mixtures or oxygen compared with air breathing. The clinical implication of these findings might be that heliox 50:50 is the mixture of choice for the treatment of decompression sickness.

Effects of muscle perfusion pressure on fatigue and systemic arterial pressure in human subjects

1999 ◽  
Vol 86 (3) ◽  
pp. 845-851 ◽  
Author(s):  
Julie R. Wright ◽  
D. I. McCloskey ◽  
Richard C. Fitzpatrick
Keyword(s):  
Blood Pressure ◽  
Perfusion Pressure ◽  
Human Subjects ◽  
Normal Subjects ◽  
Voluntary Contraction ◽  
Muscle Performance ◽  
Central Blood Pressure ◽  
Human Hand ◽  
Adductor Pollicis Muscle ◽  
Arterial Perfusion

The effects of changes in arterial perfusion across the physiological range on the fatigue of a working human hand muscle were studied in seven normal subjects. With the hand above heart level, subjects made repeated isometric contractions of the adductor pollicis muscle at 50% of maximal voluntary contraction in a 6-s on, 4-s off cycle. To assess fatigue, a maximal isometric twitch was elicited in each “off” period by electrical stimulation of the ulnar nerve. The experiment was repeated at least 2 days later with the hand at heart level. Five subjects showed faster fatigue with the arm elevated, and two subjects showed little difference in fatigue for the two conditions. Central blood pressure rose in proportion to fatigue for the subjects overall and returned quickly to its initial level afterwards. We conclude that human muscle fatigue can be increased by physiological reductions in perfusion pressure. Central blood pressure increases as the muscle fatigues, a response that may partially offset declining muscle performance.

Role of vagal feedback from the lung in hypoxic-induced tachycardia in humans

1995 ◽  
Vol 78 (4) ◽  
pp. 1522-1530 ◽  
Author(s):  
P. M. Simon ◽  
B. H. Taha ◽  
J. A. Dempsey ◽  
J. B. Skatrud ◽  
C. Iber
Keyword(s):  
Lung Transplant ◽  
Human Subjects ◽  
Cardiovascular Responses ◽  
Normal Subjects ◽  
Chronotropic Response ◽  
Transplant Patients ◽  
Marked Variability ◽  
Arterial O2 Saturation ◽  
Mild Hypoxia

We assessed the cardiovascular responses to systemic normocapnic hypoxia in five normal subjects, five double lung transplant patients with lung denervation and intact hearts, and five patients with denervated hearts. Progressive normocapnic hypoxia was induced over 10–15 min and maintained for 2–3 min each at 90, 87, 84, and 80% arterial O2 saturation (SaO2). Normal subjects showed the most pronounced mean increase in heart rate (dHR/dSaO2 = 0.86 +/- 0.13 beat/min per 1% SaO2). Three lung-denervated subjects had normal tachycardiac responses (1.6, 0.9, and 0.69 beats/min per 1%), whereas the other two had distinctly lower responses (0.34 and 0.39 beat/min per 1%). Most of the lung-denervated subjects also showed a significant tachycardia with even mild hypoxia; none showed a bradycardiac response to any level of hypoxia. In the heart-denervated group, hypoxic tachycardia was significantly lower than normal (0.29 +/- 0.13 beat/min per 1%). We conclude that vagal feedback from the lungs is not required for the normal chronotropic response to hypoxia in humans; however, this mechanism may contribute significantly to the marked variability in hypoxic-induced tachycardia found among human subjects. These data in humans contrast with the progressive bradycardiac response to hypoxia reported in vagally denervated (or nonhyperpneic) dogs and cats.

Gaits Classification of Normal vs. Patients by Wireless Gait Sensor and Support Vector Machine (SVM) Classifier

2017 ◽  
Vol 5 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Taro Nakano ◽  
B.T. Nukala ◽  
J. Tsay ◽  
Steven Zupancic ◽  
Amanda Rodriguez ◽  
...  
Keyword(s):  
Support Vector Machine ◽  
Real Time ◽  
Human Subjects ◽  
Wearable Sensors ◽  
Normal Subjects ◽  
Support Vector ◽  
Svm Classifier ◽  
Time Dynamic ◽  
Linear Svm ◽  
Dynamic Gait

Due to the serious concerns of fall risks for patients with balance disorders, it is desirable to be able to objectively identify these patients in real-time dynamic gait testing using inexpensive wearable sensors. In this work, the authors took a total of 49 gait tests from 7 human subjects (3 normal subjects and 4 patients), where each person performed 7 Dynamic Gait Index (DGI) tests by wearing a wireless gait sensor on the T4 thoracic vertebra. The raw gait data is wirelessly transmitted to a near-by PC for real-time gait data collection. To objectively identify the patients from the gait data, the authors used 4 different types of Support Vector Machine (SVM) classifiers based on the 6 features extracted from the raw gait data: Linear SVM, Quadratic SVM, Cubic SVM, and Gaussian SVM. The Linear SVM, Quadratic SVM and Cubic SVM all achieved impressive 98% classification accuracy, with 95.2% sensitivity and 100% specificity in this work. However, the Gaussian SVM classifier only achieved 87.8% accuracy, 71.7% sensitivity, and 100% specificity. The results obtained with this small number of human subjects indicates that in the near future, the authors should be able to objectively identify balance-disorder patients from normal subjects during real-time dynamic gaits testing using intelligent SVM classifiers.

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