bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hypoxic-hypercapnic interaction in subjects with bilateral cerebral dysfunction
Authors: Plum Fred , Brown Harold W. 
Published: December 2017

To analyze cerebral influences modifying autonomic respiratory responses, we compared normals and patients with bilateral pyramidal tract disease for their ventilatory response to hypoxia and hypoxia-hypercapnia. During eucapnia, the two groups showed similar hypoxic responses. During hypercapnia, the ventilatory response to hypoxia was greater in the brain-damaged subjects. This apparent augmentation, however, was due entirely to anoxia interacting with an abnormally facilitated carbon dioxide sensitivity: compared with normals, brain-damaged patients at PaOO2 90–100 mm Hg showed an 85% greater CO2 response, and at PaOO2 50 mm Hg showed a 79% greater CO2 response. Since cerebral dysfunction facilitated the ventilatory response to hypoxia-hypercapnia combined but not the response to hypoxia alone, the results imply that the two respiratory stimuli interact centrally rather than peripherally. respiration; brain damage; interaction; carbon dioxide response; forebrain effects; ventilation with CNS disease Submitted on February 18, 1963
Effect of a fatty meal on whole blood and plasma viscosity
Authors: Charm S. , McComis W. , Tejada C. , Kurland G. 
Published: December 2017

The viscosity of whole blood of 40 medical students measured with a Brookfield cone and plate viscometer showed no change before and after a fatty meal although the serum lipids increased. In separate experiments, no change was noted in plasma viscosity as determined by the capillary tube technique although plasma lipids increased. From theoretical considerations, it was suggested that methods of determining viscosity within a 2% error would be necessary in order to detect changes in plasma and whole blood viscosity after a fatty meal. However, even with the GDM low-shear rate coaxial viscometer, which has an accuracy reputed to be 2%, no change was observed in the whole blood or plasma viscosity. The results with the GDM viscometer compared favorably with the results from the Brookfield cone and plate viscometer. In 2 out of 52 cases a definite decrease in whole blood viscosity was found 3 hr after a fatty meal. The plasma viscosities, however, did not change. It is postulated that in rare cases a decrease in the yield stress of the cell aggregates due to the increased lipids results in a decreased blood viscosity. The mechanics by which this occurred is under study. dietary fat; viscosity of blood Submitted on June 15, 1963
Steroid and catecholamine studies on pilots during prolonged experiments in a space cabin simulator
Authors: Ulvedal F. , Smith W. R. , Welch B. E. 
Published: December 2017

Urinary excretion of 17-hydroxycorticosteroids, corticosterone-like hormones, and catecholamines (epinephrine and norepinephrine) has been investigated on pilots during prolonged experiments in a two-man space cabin simulator. The experimental profiles were: 1) two 17-day experiments at ground level; 2) two 14-day experiments at 27,000 ft; and 3) four experiments at 33,500 ft lasting 17 days. In the latter two groups the atmosphere was essentially 100% O2. The hormone parameters indicate that conditions imposed by the experimental procedures were no more stressful to the subjects than undergoing extensive medical examinations as observed from pre- and postexperimental values. The only significant trend was the continuous linear increase in the excretion of corticosterone-like hormones. There were borderline indications that the excretion of 17-hydroxycorticosteroids and norepinephrine were altitude dependent. Extraordinary occurrences in the simulator were correlated with increased catecholamine and steroid excretion. The correlation coefficients and the analyses of variance for the four hormone parameters were calculated and discussed. endocrinology; sealed environments; stress hormones Submitted on March 26, 1963
Apparatus for determination of zeta potentials from streaming potentials
Authors: Beck R. E. , Mirkovitch V. , Andrus P. G. , Leininger R. I. 
Published: December 2017

A system was developed to measure the streaming potential generated between the ends of a capillary by the flow of a fluid through the capillary. Zeta potential can be calculated from the streaming potential. Adequate sensitivity and reproducibility were achieved by making special electrodes: silver wires plated in KCl solution and embedded in agar, careful electrical shielding, and provision for reversal of flow through the capillary to minimize electrode errors. The apparatus was developed to measure streaming potentials generated by either RingerS's solution or blood in contact with capillaries made of different materials such as quartz, polyethylene, etc. An example of a determination using a quartz capillary is presented. interfaces; blood; salt solutions; glass; quartz Submitted on February 25, 1963
Volumetric dynamics of respiration as measured by electrical impedance plethysmography
Authors: Allison R. D. , Holmes E. L. , Nyboer J. 
Published: December 2017

Electrical resistive impedance changes of the chest related to pulmonary air volumes were quantitatively evaluated in ten normal male adults. A four-electrode, 100-kc, electrical impedance plethysmograph was used for these determinations. A 13.5-liter Collins respirometer was used to measure changes in pulmonary gas volume. In all studies reported the electrodes were positioned on the posterior aspect of the thorax. The current was delivered to the outer pair with one attached to the neck and the other below the level of the diaphragm. The voltage drop related to variations in resistance was detected between the inner two electrodes at a constant length of 30 cm. Inspiration and expiration were associated with changes in electrical resistive impedance. Calculations of changes in pulmonary gas volumes were based on electrical variations associated with respiration. The calculated values closely approximated recorded volumes on the spirometer for values of 100–2,500 ml. This technique would eliminate carbon dioxide absorbents, nose clips, conventional airway hindrances and have adequate frequency response for a normal range of test conditions. Some of the limitations in the practical application of the system currently under study are discussed. pulmonary air volume determination; resistive impedance; measurements of the chest; pulmonary function; respiration Submitted on April 17, 1963
Minimal air in dogs
Authors: Kleinman Leonard I. , Poulos Dennis A. , Siebens Arthur A. 
Published: December 2017

The “minimal air” of supine dogs was measured by subtracting from the functional residual capacity the volume expelled from the lungs when the sternum was widely split. Minimal air/functional residual capacity, minimal air/lung weight, and minimal air/animal weight were 57.0 ± 8.6%, 9.51 ± 2.92 ml/g, 21.8 ± 4.2 ml/kg, respectively. The correlation coefficient of minimal air with functional residual capacity was .79 (P < 1%), of minimal air with animal weight was 0.70 (P < 1%), and of minimal air with lung weight was .67 (P < 5%). The ratio minimal air/functional residual capacity of these dogs compared with the ratio residual volume/functional residual capacity of supine men. The airway component of the minimal air was approximately 36% and the alveolar component approximately 64%. The lungs contained the minimal air at a time when airways were patent rather than collapsed. functional residual capacity; residual volume Submitted on March 11, 1963
Effect of temperature on arterial blood gas tensions and pH during exercise
Authors: Holmgren Alf , McIlroy Malcolm B. 
Published: December 2017

We measured arterial blood Po2, Pco2 and pH at rest and during a standard exercise test on a bicycle ergometer in ten normal subjects. In five we measured esophageal and five arterial blood temperature during the exercise and corrected the arterial blood values to the temperature at the time the samples were collected. We found an average rise in temperature of 1 C (range 0.2–1.6 C) during exercise lasting about 30 min at loads up to an average of 1,200 kg-m/min. At the highest load the average correction for PaOO2 was 5.6 mm Hg, for PaCOCO2 1.6 mm Hg and for pH 0.014 units. Our corrected values showed a fall in PaCOCO2 and pH and a rise in PaOO2 during severe exercise. These findings are compatible with the development of a metabolic acidosis during severe exercise and indicate that our subjects were not limited by diffusion across the alveolar-capillary membrane. metabolic acidosis; alveolar capillary membrane diffusion; hyperventilation; PaOO2 and PaCOCO2 in severe exercise Submitted on June 17, 1963
Mechanical work in running
Authors: Cavagna G. A. , Saibene F. P. , Margaria R. 
Published: December 2017

The external and internal mechanical work in running has been measured through various procedures. Different from walking, in running the work due to the forward speed changes (variation of kinetic energy) and to the vertical displacement of the center of gravity (variation of potential energy), throughout the step cycle, are substantially in phase. The external work performed per kilometer is independent of speed, amounting to 0.25 kcal/kg km. The total mechanical work amounts to about 0.40–0.50 kcal/kg km. The efficiency in running has been calculated as about 40–50%: such a high value involves a contribution of a substantial amount of energy delivered at a very low cost; this appears to be identified as elastic recoil energy from the stretched contracted muscle and amounts to about half the energy spent in running. A mechanical model is given for the walking and running processes. mechanics of locomotion; kinetic and potential energy during step cycle; elasticity of contracted muscle; mechanical models for walking and running Submitted on July 29, 1963
Cytology of human bone marrow subjected to prolonged storage at -79 C
Authors: Pegg D. E. 
Published: December 2017

It was observed that human bone marrow cells preserved at -79 C with 15% glycerol exhibited marked morphological changes when examined by conventional cytological methods, and that techniques designed to remove glycerol slowly produced still more damage. By contrast, cells from which the glycerol was removed rapidly by abrupt dilution in an isotonic medium were found to be morphologically intact when examined on cellulose acetate membrane filters: the quantitative recovery was 74%, and undoubted proof of viability was provided by the demonstration of motile cells. When bone marrow was examined after storage for periods up to 3 frac12 years it was noted that a progressive loss of cells occurred, and a variety of cytological techniques, including staining by Romanowsky, Feulgen, PAS, Sudan black, and pyronin techniques and supravital staining with acridine orange and trypan blue all provided further evidence of progressive deterioration during storage at -69 to -79 C. human bone marrow preservation; human bone marrow viability; cryobiology Submitted on May 20, 1963
Determination of tissue volume and carbon dioxide dissociation slope of the lungs in man
Authors: Sackner Marvin A. , Feisal Khalil A. , DuBois Arthur B. 
Published: December 2017

The volume of N2O absorbed by the lung can be measured during inspiration before the gas is taken up in significant amounts by the capillary blood flow by a plethysmographic technique. If the alveolar fraction of N2O and its solubility coefficient are known, the combined pulmonary tissue and capillary blood volume (Vt+c) can be calculated. Vt+c averaged 517 ml, sd 61 ml, in nine adult males, values in good agreement with those obtained by other methods. The pulmonary tissue volume alone, Vt, in six of these subjects was 438 ml, sd 58 ml. A modification of the technique, using CO2 as the test gas, permitted calculation of the CO2 dissociation slope of the lung tissue. In five subjects, the CO2 dissociation slope of the lung, without the buffering effect of pulmonary capillary blood, over a range of PaCOCO2 from 31 to 55 mm Hg, averaged 0.30 ml CO2 STPD/100 ml lung tissue per mm Hg, or including physically dissolved CO2, 0.38 ml CO2 STPD/100 ml lung tissue per mm Hg. Because Vt is about four times larger than Vc, the lung tissue is of greater importance than the pulmonary capillary blood in buffering fluctuations in alveolar carbon dioxide during respiration. pulmonary tissue volume; pulmonary tissue space for N2O Submitted on August 26, 1963
A radio telemetering device
Authors: Barry William 
Published: December 2017

A radio telemetering device is presented in detail and successful operation in transmitting the electrocardiogram of the freely moving human subject at ranges up to 200 yards is claimed. The linear nature of its frequency response will permit quantitative rather than qualitative investigations to be made of any physiological variable when this transmitter unit is used with the appropriate transducer. radio-transmitted ECG signals; portable ECG; biologic amplifiers; electronic ECG recording Submitted on August 19, 1963
Fashioning polyethylene tubing for use in physiological experiments
Authors: Heatley Norman G. , Weeks James R. 
Published: December 2017

Working instructions are given, with diagrams, for simple methods of joining, bending, sealing, and reinforcing fine plastic tubing, chiefly of polyethylene; for making it larger or smaller, for fabricating cannulas, T pieces, and multiway junctions; and for connecting it to other pieces of apparatus. physiological techniques using polyethylene tubing; polyethylene tubing, physiological uses; tubing, polyethylene, fashioning techniques; methods, physiological, using polyethylene tubing; physiology, laboratory techniques for polyethylene tubing Submitted on November 8, 1963
Cerebral hematocrit in normal man
Authors: Larsen O. Andrée , Lassen Niels A. 
Published: December 2017

The cerebral mean circulation times of plasma and erythrocytes and the cerebral hematocrit were determined by injection of I131-labeled albumin and Cr51-labeled erythrocytes into an antecubital vein, drawing multiple blood samples simultaneously from the carotid artery and the internal jugular vein, and calculating the arteriovenous concentration differences. The total body hematocrit was determined from equilibrium concentrations. In ten normal subjects the average cerebral hematocrit was 92.2% of the large vessel hematocrit, this difference being highly significant (P < 0.001). The total body hematocrit averaged 88.6% of the large vessel value and was significantly lower (P < 0.01) than for the brain. As the cerebral vascular bed has protein-tight capillaries, it is concluded that this area contains an extra plasma volume inside the vessel walls. It is suggested that the oft-repeated finding of a body hematocrit of about 90% of the large vessel hematocrit is mainly due to excess intravascular plasma localized to all the minor vessels in the body. cerebral mean circulation time; cerebral blood volume; body hematocrit Submitted on January 6, 1964
Effect of exercise on free fatty acid levels in the pigeon
Authors: George J. C. , Vallyathan N. V. 
Published: December 2017

The effect of exercise on the free fatty acid (FFA) levels in the muscle, liver, adipose tissue, and blood in the pigeon was quantitatively studied after the electrical stimulation of the breast muscles. A reduction of FFA in the blood plasma, liver, and adipose tissue was observed after the stimulation of the muscle. On the other hand, an increase in the FFA content of the muscle was noticed. It was found that there is high rate of FFA extraction by the muscle from the blood which in turn is being supplied from the adipose tissue and liver during the activity of the muscle. From the data obtained it is concluded that the skeletal muscles of birds utilize mainly fat during sustained muscular activity. The physiological importance of FFA as substrate for muscular activity is discussed. fat utilization by muscle; fatty acid release from adipose tissue and liver; blood lipid level in exercise Submitted on September 25, 1963
Blood-gas transfer, hemolysis, and diffusing capacity in a bubble tonometer
Authors: Ravin Mark B. , Briscoe William A. 
Published: December 2017

The performance of a test-tube tonometer is described. The 95% equilibration times in 10 ml blood are 2.9 and 14 min, respectively, with small and large bubbles at a bubble flow rate of 1 ml/sec. Small bubbles have the disadvantage that surface tension significantly raises gas pressure above atmospheric. With large bubbles surface tension effects are negligible and hydrostatic pressure is only about 0.5% of an atmosphere. Hence, large bubbles are preferred for calibrating an oxygen electrode for use with blood of a high Po2. Hemolysis produces less than 150 mg/100 ml plasma hemoglobin in the time needed for equilibration. The diffusing capacity for oxygen of the bubble interface in 10 ml blood in the tonometers is about 0.001 and 0.008 ml mm-1 sec-1 with large and small bubbles, respectively, when blood Po2 is about 20 mm Hg, and is one-tenth as much when blood Po2 is over 500 mm Hg. This type of tonometer appears to be a useful adjunct to the oxygen electrode. oxygen; equilibration Submitted on July 1, 1963
Relationship of changing bronchial caliber to respiration in the dog
Authors: Colgan Frank J. 
Published: December 2017

A cylindrical bronchial catheter is described for recording moment-to-moment changes in caliber during spontaneous respiration in lightly anesthetized dogs. Caliber changes due to bronchial transmural pressure and altered bronchial tone are measured separately and collectively. Transmural pressure changes, because of the elastic character of bronchi, are shown to alter caliber significantly. Histamine-induced alterations in bronchial tone are capable of dominating transmural pressure influences on caliber. Following small doses of intravenous histamine, dynamic compliance decreases progressively and the decrease is related in time and degree to changes in bronchial caliber. Recovery is prompt and sustained. Decrease in compliance occurs without significant increase in airway resistance or change in functional residual capacity. These observations suggest that a dominant factor influencing dynamic compliance is alteration of bronchomotor tone. bronchial distensibility; bronchoconstriction; bronchomotor tone; transbronchial pressure; compliance; mean airway resistance; histamine Mecholyl Submitted on January 6, 1964
An isothermal system for manometric measurement of changes of volume
Authors: David A. , Greenfield M. 
Published: December 2017

The volume of gas to be measured is displaced into a reservoir which is so constructed that its contents undergo nearly perfect isothermal compression, raising the pressure by up to 1 mm Hg relative to the pressure in an identical compensating reservoir. The conditions of compression ensure a stable calibration over a wide range of rates of gas displacement, and the use of a compensating reservoir makes the system quite independent of fluctuations in barometric pressure, and largely independent of fluctuations in ambient temperature. volume recorder; air displacement recorder; barometric measurement of volume Submitted on December 9, 1963
Vestibular habituation during repetitive complex stimulation: a study of transfer effects
Authors: Guedry Fred E. , Collins William E. , Graybiel Ashton 
Published: December 2017

Thirty-two men were rotated at 7.5 rev/min while facing the center of the Pensacola slow rotation room for several hours. The men were seated 4 ft from the center of rotation; direction of rotation was toward the subject's left. During rotation, subjects were immobile except for series of measured head movements restricted to the frontal plane and to a particular quadrant of that plane for each subject. Nystagmus, illusory phenomena, and nausea were reduced by this procedure, but this habituation did not transfer to other forms of vestibular stimulation including that induced by head movements in an “unpracticed” quadrant of the same plane. Residual effects exhibited in “static tests” after the habituation program were primarily restricted to the practiced quadrant. habituation; nystagmus; vestibular function Submitted on January 15, 1964
Heart rate during transition from rest to exercise, in relation to exercise tolerance
Authors: Davies C. T. M. , Harris E. A. 
Published: December 2017

Thirty-four healthy subjects of different ages and sex have been studied during exercise on a motor-driven treadmill. Heart rate was measured continuously, oxygen consumption was measured during the steady state of exercise, and in 15 subjects the maximum oxygen consumption was also determined. From these data three standard indices of working capacity were calculated, together with an index based upon the "pulse deficit" of early exercise, for comparison with each other and with the maximum oxygen consumption. The "pulse deficit index" was found to express relative working capacity slightly better than any of the standard indices. working capacity and heart rate; pulse deficit of exercise Submitted on November 19, 1963
Physiological reactions to heat of Bushmen and of unacclimatized and acclimatized Bantu
Authors: Wyndham C. H. , Strydom N. B. , Ward J. S. , Morrison J. F. , Williams C. G. , Bredell G. A. G. , Von Rahden M. J. E. , Holdsworth L. D. , Van Graan C. H. , Van Rensburg A. J. , Munro A. 
Published: December 2017

Bushmen in the Kalahari desert fulfill two criteria for acclimatization to heat. They exercise actively, in hunting, in relatively severe heat in midsummer. Compared with unacclimatized Bantu they have higher sweat rates per square meter and lower heart rates. However, rectal temperatures are not much lower than those of unacclimatized Bantu. River Bushmen present a paradoxical picture. In summer sweat rates are higher than in winter, but are not as high as desert Bushmen. Summer heart rates are, however, higher than in winter. Rectal temperatures in the two seasons are similar. The higher sweat rates in summer are good evidence of better acclimatization than in winter; the higher heart rates may be a reflection of differences in physical fitness in the two seasons. association of morphology and metabolism on cold exposure; cold responses of Bantu, Bushmen, and Caucasians; heat conductance and skinfold thickness in cold; metabolisms of Bantu, Bushmen, and Caucasians in cold; toe, finger, and rectal temperatures of different ethnic groups in cold Submitted on February 4, 1964
Influence of temperature on blood pH of the human adult and newborn
Authors: Adamsons Karlis , Daniel Salha S. , Gandy Gillian , James L. Stanley 
Published: December 2017

The effect of temperature upon pH of blood from adult and newborn humans was investigated. Although the mean ΔpH/ΔT values for the two populations differed, 0.0144/ °C for adults versus 0.0128 for the newborn, this was not peculiar to the source since the temperature-induced pH changes were identical when comparison was made between samples of similar pH and CO2 content. It was shown that even over the physiologic pH range ΔpH/ΔT is not constant but is a function of pH and CO2. No significant changes in ΔpH/ΔT were observed with oxygenation of hemoglobin. The influence of red cell concentration was detectable only when hematocrit values fell below 20%. A graph and an equation for the determination of ΔpH/ΔT of blood with a given pH and CO2 content is presented. acid base Submitted on December 9, 1963