bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of respiration and heart rate response in exercise during altitude acclimatization
Authors: Dejours Pierre , Kellogg Ralph H. , Pace Nello 
Published: December 2017

In three subjects pulmonary ventilation, alveolar gas, blood lactate, and heart rate were studied at rest and during two grades of treadmill exercise in four environmental conditions: at sea level breathing air or 13% O2 (simulating altitude), and during a sojourn of 3 weeks at an altitude of 3,800 m breathing air or 33% O2 (simulating sea level). At altitude, ventilatory response to exercise was decreased by inhalation of 33% oxygen but remained above that observed at sea level breathing air. Study of the transients at the beginning and end of exercise showed that in all four environmental conditions, the ventilatory response to exercise could be dissected into fast and slow components, interpreted as neurogenic and humoral, respectively, in accordance with the neurohumoral theory. In two subjects, the increased hyperpnea of exercise at altitude represented increases in both the neurogenic and humoral components, while in the third subject only the humoral component was increased. Study of the composition of alveolar gas at the start and end of exercise indicated that pulmonary blood flow as well as ventilation undergoes immediate change at these times. Resting blood lactate concentrations and the increment produced by exercise were higher at altitude and resting heart rate tended to increase throughout the altitude sojourn in these subjects. The increment in pulse rate produced by exercise fell progressively, as expected. Submitted on February 5, 1962
A mathematical approach to hemodialysis
Authors: Yoder Richard D. 
Published: December 2017

Hemodialysis may be investigated by utilizing a laboratory system composed of a reservoir, hemodialysis unit, and bath solution. The effect of the Kolff-type dialysis unit is to permit diffusion of solute and to filter solvent and solute while pressure decreases along the length of its tubing. Kinetic equations in which the length of the dialysis tubing is the independent variable describe these processes in terms of the gradients of pressure, solvent flow rate, and solute concentration. Changes of volume and solvent concentration in the wash and reservoir solutions are functions of time and of the net effect of the dialysis unit at a given time. The complete set of general equations describes the behavior of the system. Functions for the equations of the wash and reservoir solutions are easily derived. An inflatable ellipse is selected as an appropriate geometric shape for the cross section of the dialysis tubing and functions are derived for the equations of the dialysis unit. Submitted on March 9, 1962
Reflex pulmonary hypertension of fresh-water aspiration
Authors: Colebatch H. J. H. , Halmagyi D. F. J. 
Published: December 2017

The mechanism of the pulmonary hypertension produced by the aspiration of 1 ml/kg fresh water was investigated in sheep which were intubated and lightly anesthetized with thiopentone. The pulmonary hypertension was reduced by breathing 100% oxygen and by hexamethonium bromide; it was almost completely abolished by atropine sulfate, an infusion of adrenaline or isoproterenol, and by aerosol isoproterenol. Vagotomy, bretylium tosylate, reserpine, acetylcholine by infusion, tetracaine, and lysergic acid butanolamide were ineffective. In most cases aspiration of water produced little change in cardiac output measured by the Fick method. These findings show that aspiration of water excites a local reflex response of the parasympathetic nervous system, producing pulmonary vasoconstriction. The increase in pulmonary artery pressure could not be causally related to the accompanying fall in arterial oxygen saturation or to the change in lung mechanics. The relation of this new form of pulmonary hypertension to the responses of the pulmonary vessels, previously described, is discussed. Submitted on May 7, 1962
Species difference in pancreatic lipolytic and amylolytic enzymes
Authors: Zieve Leslie , Vogel William C. , Kelly William D. 
Published: December 2017

The pancreatic content of lecithinase A in man is approximately 10–20 times that in the dog. In contrast, the pancreatic content of lipase is one-half and of amylase one-sixth that of the dog. The rabbit is similar to man in its pancreatic amylase and lipase content, and to the dog in its lecithinase A content. In man the serum lecithinase A increases during acute pancreatitis, paralleling more or less the elevations in serum amylase and lipase. Though individual discrepancies are noted, all three enzymes increase roughly proportionately. During acute pancreatitis in the dog, the serum lecithinase A increases but slightly, in sharp contrast to the elevations in serum amylase and lipase which are greater than in man. Submitted on July 12, 1962
Frequency components and positional changes in electrocardiogram of the adult rat
Authors: Angelakos Evangelos T. , Bernardini Pamela 
Published: December 2017

Standard limb electrocardiograms of the adult rat (4–5 months old) were studied using cathode-ray oscillographic techniques. Fourier analysis revealed that the main QRS components can be represented with sine-wave frequencies of 50–400 cycles/sec. Gross distortion was observed with filters providing a high-frequency response of less than 250 cycles/sec. The mean QRS axis was found to be quite sensitive to positional changes. Submitted on August 8, 1962
In vivo activation of the fibrinolytic enzyme system of dogs
Authors: Taylor Fletcher B. , Singleton John , Bickford Arthur F. 
Published: December 2017

We studied the effect of streptokinase and small amounts of human plasmin on the components of the fibrinolytic enzyme system of the dog. A 1-hr infusion of streptokinase (500 U/ml blood volume) and plasmin (.001 mg/ml blood volume) in dogs produced during the infusion: 1) No adverse immune reaction. 2) Enhanced lysis of blood clots. 3) Decreased serum plasminogen and plasma plasmin inhibitor levels. 4) Decreased plasma fibrinogen levels. The clot lysis rates, plasminogen, and plasma plasmin inhibitor levels returned to one-half their preinfusion level within 4–8 hr. The fibrinogen level returned to one-half its preinfusion level after 12 hr. Submitted on September 10, 1962
Alveolar gas exchange during submarine escape
Authors: DuBois Arthur B. , Bond George F. , Schaefer Karl E. 
Published: December 2017

Solution of an equation for alveolar gas exchange during underwater ascent indicates that alveolar carbon dioxide tension should remain constant and normal during ascent owing to the expansion of gases in the lungs. Alveolar gas samples were obtained before and at the end of buoyant ascent from a depth of 90 ft of water. The partial pressure of alveolar carbon dioxide at the end was approximately equal to that at the beginning, as predicted, and the partial pressure of oxygen indicated that the arterial saturation would be almost normal. These findings indicate that buoyant ascents can be made from a depth of at least 90 ft without breathing and without urgency to breathe. Extrapolation of these findings indicates that during ascents from much greater depths there should be little or no urgency to breathe. Submitted on August 8, 1962
Pulmonary circulation and oxygen transport in lambs at high altitude
Authors: Reeves John T. , Grover Estelle B. , Grover Robert F. 
Published: December 2017

The oxygen transport and pulmonary hemodynamics of lambs native to low altitude were evaluated in Denver and on Mount Evans (12,700 ft.). Because the Hb-O2 dissociation curve is placed well to the right of most other mammals, markedly depressed arterial O2 saturations (59%) occurred at high altitude. However, the lambs adapted remarkably well and showed normally rapid growth. The mixed venous Po2 was relatively well maintained, primarily by a narrowing of the A-V Po2 gradient to 11 mm Hg. Despite the marked hypoxemia, elevation of the pulmonary artery pressure was not a consistent finding, and when it occurred it was neither marked nor sustained. Submitted on June 6, 1962
Compliance of the chest wall in chronic bronchitis and emphysema
Authors: Cherniack R. M. , Hodson A. 
Published: December 2017

The respiratory rate was found to be faster and the tidal volume lower than normal in patients with chronic bronchitis and emphysema. The compliance of the total respiratory system, the lungs, and the chest wall was measured in 11 normal subjects and 13 patients with chronic bronchitis, 11 of whom had also developed emphysema. The compliance of the total respiratory system was lower than in the normals in the patients with chronic bronchitis. This was entirely attributable to a reduction in the compliance of the chest wall, that of the lungs being similar to that of the normals. The vital capacity appeared to be related to the compliance of the total respiratory system and was reduced in the patients with chronic bronchitis and emphysema largely because of a diminished distensibility of the chest wall. It is suggested that the low chest wall compliance may explain the paradoxical finding of rapid shallow respirations in these patients with airway obstruction who theoretically would have been expected to breathe slowly and deeply. It is further suggested that the diminished distensibility of the chest wall in patients with chronic bronchitis and emphysema would necessitate an increase in the amount of work done in order to breathe and, therefore, likely contributes to the disability in this disease. Submitted on April 18, 1962
Influence of temperature on olfactory sensitivity
Authors: Stone Herbert 
Published: December 2017

The olfactory response to acetic acid was studied at six experimental temperatures (12.5, 15, 20, 25, 30, and 35 C) for a trained panel of ten subjects. Determination of the 50% thresholds indicated no significant differences in olfactory sensitivity at the various environmental temperatures. Further analysis of the data indicated two significantly different groups of differing absolute sensitivity; however, no influence of temperature on olfactory sensitivity was noted. The 50% threshold for acetic acid was found to be 39.0 x 10-4 mg/liter air (0.65 x 10-7 moles/liter air) for the pooled data. Temperature recordings of inhaled and exhaled air in the nasal cavity suggested inspired air was rapidly equilibrated with body temperature by heat provided by the conchae. These data corroborate the conclusions of the sensory tests and explain the lack of change in odor threshold at different environmental temperatures. The inspired air stream is rapidly warmed to body temperature and any apparent changes in olfactory sensitivity would appear to be physical phenomena and not response to a true olfactory stimulus. Submitted on January 10, 1963
Aerobic working capacity of Eskimos
Authors: Andersen K. Lange , Hart J. S. 
Published: December 2017

The aerobic working capacity was measured in eight young Eskimos. Their maximal oxygen uptake averaged 2.6 liter/min. This is considerably lower than that found in young Caucasian men. The heart rate-oxygen uptake relationship also indicates a lower physiological capacity of the Eskimos. Expressing maximal oxygen uptake on a body weight basis brings about substantial agreement with results of experiments on sedentary-living Scandinavian students. The heart rate taken at the end of the maximal work averaged 173 min for the Eskimos which is about 10% lower than found in Caucasian men, indicating that the work test (bicycling) did not activate the circulatory system of the Eskimos maximally. By assuming a linear correlation between heart rate and O2 consumption up to its maximal value, the maximal O2 uptake would have to be 20% greater to give a maximal heart rate similar to that observed in Caucasian men. The pulmonary ventilation efficiency during exercise was found to be lower in Eskimos than in Caucasian men. Submitted on February 7, 1963
Effect of exercise on Na and K concentrations in human saliva and serum
Authors: Salminen Simo , Konttinen Aarne 
Published: December 2017

The effect of exercise on the salivary Na, K, and protein concentrations and on the serum Na and K concentrations has been studied in young men. The exercise consisted of a march of 2-hr duration. The exercise had no marked effect on the serum Na and K. The salivary Na concentration increased nearly twofold during exercise, and had decreased to its initial value within 2-hr recovery. No noteworthy changes in the salivary K concentration occurred during the experiment. The salivary protein concentration increased during exercise, and this increase was positively correlated with the increase in the salivary Na/K ratio in the same man. These results are ascribed to the increased permeability of the plasma-saliva barrier during the exercise. Submitted on September 4, 1962
Validation of insorption by blood analysis with comparisons of systemic and portal venous disappearances of D2O, Na24, and K42
Authors: Code Charles F. , Moll Johann C. , Orvis Alan L. 
Published: December 2017

The rates of disappearance D2O, Na22/24 and K42 from the arterial blood were determined in 17 dogs following rapid injection of the isotopes into the femoral and portal veins. Differences between systemic and portal venous injections were significant during the early phases of the disappearance of the isotopes (P < 0.05). Systemic insorption was simulated by continuous intravenous injection of D2O, Na22, and K42 at known rates into the femoral vein. The appearance of the isotopes in the arterial blood was determined repeatedly during and after their injection. The rate of injection (simulated insorption) was calculated using the mean systemic arterial disappearance rate. The differences between the calculated and actual rates of injection were insignificant. When portal insorption was simulated by constant injection of the isotope into the portal vein, the calculated rate of injection was not significantly different from the actual rate if the mean portal arterial disappearance curve was used in the calculation. When the systemic arterial disappearance curve was utilized, the calculated rate of injection was slightly faster than the actual rate. Submitted on July 11, 1962
Cardiopulmonary manifestations with high O2 tensions at atmospheric pressure
Authors: Smith Charles W. , Lehan Patrick H. , Monks James J. 
Published: December 2017

Dogs inhaled 95–98% oxygen at atmospheric pressures until they succumbed of respiratory failure after an average of 54.6 hr. At autopsy the lungs were dark red, hemorrhagic, edematous, and congested. Blood gas contents and cardiovascular parameters were maintained essentially normal until approximately 2–3 hr before death. Tidal volume increased, respiratory rate slowed, and intrapleural pressures changed markedly. Pulmonary compliance decreased late in exposure, presumably due to increased turgor of the lungs. Maintenance of normal left atrial pressures was judged to show that left ventricular function was not responsible for the pulmonary edema and congestion. oxygen toxicity Submitted on January 14, 1963
Body temperature as a determinant in maze acquisition by mice
Authors: Sudak Frederick N. , Essman Walter B. 
Published: December 2017

The effect of increasing the number of training trials and spacing training sessions on acquisition of a simple water-escape response was investigated in mice during a moderate reduction in colonic temperature. Hypothermia was produced by treatment of the animals with 50 mg/kg 2,4-dichlorophenoxyacetic acid (2,4-D) (i.p.) and a 30-min exposure to cold air (2.0 ± 0.5 C). Control animals received 2,4-D and were maintained in a thermoneutral environment (32.0 ± 1 C) to preclude loss of body temperature. Following these procedures, all animals were given four training trials spaced at 15-min intervals. Two days later, the procedures were repeated and four more training trials were given. Acquisition of the escape response occurred within five training trials for animals in which colonic temperatures were reduced 2.6–4.8 C during training. Control animals demonstrated acquisition of the maze habit within two training trials. These data suggest that extending the training trials over an expanded period of time was effective in allowing for acquisition in hypothermic mice and that a reduction in body temperature affects acquisition rate. animal behavior; learning in hypothermic animals; hypothermia and maze acquisition Submitted on March 6, 1963
Frequency-dependent compliance at different levels of inspiration in normal adults
Authors: Mills R. J. , Cumming G. , Harris P. 
Published: December 2017

Measurements of pulmonary compliance have been made at different respiratory frequencies in 11 normal adults. The observations have been carried out at three levels of inspiration, the constancy of the volume of air in the lungs being checked by body plethysmography. Compliance decreased with an increasing respiratory frequency at each level of inspiration. The effect was greatest at the lowest lung volume, and least at the middle lung volume. Variations in respiratory frequency had no significant effect on the pulmonary resistance. lung plethysmograph Submitted on January 31, 1963
Respiratory acclimatization to carbon dioxide
Authors: Schaefer K. E. , Hastings B. J. , Carey C. R. , Nichols G. 
Published: December 2017

Twenty-one subjects were exposed to 1.5% CO2 in 21% O2 for 42 days with pre- and postexposure periods on air for 9 days. Respiratory minute volume (Ve) and alveolar pCO2 were increased throughout the exposure to CO2. After transition to air Ve decreased, while pCO2 remained elevated for 9 days. CO2 retention with uncompensated respiratory acidosis lasted for 23 days. CO2 excretion was increased during the 9-day recovery period indicating release of CO2 from the CO2 stores. Oxygen consumption did not change significantly during the experiment. Respiratory acclimatization to CO2 involved a continuous increase in tidal volume while the respiratory rate declined slowly after an initial increase. Changes in respiratory pattern were associated with an increase in physiological and anatomical dead space. A significant increase in the arterial-alveolar pCO2 and alveolar-arterial pO2 gradient indicated the development of an alveolar dead space. The ventilatory response to 5% CO2 was markedly reduced at the end of CO2 exposure. chronic CO2 exposure; chronic hypercapnia; chronic respiratory acidosis Submitted on August 31, 1961
Effect of partial immersion in water on response of healthy men to headward acceleration
Authors: Wood Earl H. , Lindberg Evan F. , Code Charles F. , Baldes Edward J. 
Published: December 2017

Protection against the effects of headward acceleration afforded by immersion in water has been assayed in the human centrifuge on 15 trained subjects. Immersion in water to the xyphoid afforded an average protection of 1.1 ± 0.1 G for vision and ear opacity and of 1.6 ± 0.2 G for ear pulse and heart rate. Deeper immersion, to the level of the third rib at the sternum increased the protection to 1.8 ± 0.1 G for vision and ear opacity and to 2.8 ± 0.2 G for ear pulse and heart rate. The protection afforded the various physiologic variables increased with the magnitude of acceleration tested. Protection against loss of consciousness may be greater than protection against blackout and is probably similar to the protection afforded the ear pulse and heart rate. The cardiovascular reactions produced by headward acceleration are qualitatively similar with and without water immersion. This finding does not support the concept that impediment to venous return is the primary determinant of man's tolerance to headward acceleration. Visual symptoms occurred at greater amplitudes of ear pulse, and presumably also at greater blood pressures at head level, during water immersion than during control runs. vision; arterial pressure; heart rate; venous return; arterial pulse in ear Submitted on May 13, 1963
Effect of temperature on sensitivity of the finger
Authors: Irving Laurence 
Published: December 2017

Subjects reported the detection of impacts from objects falling upon the ball of the finger. At a given point on the skin a falling weight of 1 mg might be detected after falling 10 mm, and twice the weight would then be detected after falling 5 mm. Droplets of mercury expelled by a Scholander micrometer burette afforded one series of measurements. On 6 days for one subject the threshold of perceptible impact was least at about 35 C. It increased rapidly as the finger was cooled with Q10 = 4.5 from 35 C to 30 C and with Q10 = 2.5 from 30 C to 20 C. In five other subjects falling droplets of mercury and falling steel ball bearings showed the threshold for detection to increase rather regularly for each individual as the skin was cooled, but on various individual rates with Q10 from 2 to 10. The variation in threshold sensation for impact with temperature raises the question of how heterothermous organisms can estimate and react suitably to some peripheral conditions which must be assessed on absolute scales by means of neural processes that are so thermolabile. impact tests; sensitivity of finger skin; thermolabile sensation and integration; nervous integration Submitted on May 20, 1963
Dual purpose pressure chamber with automatic safety devices for animal studies
Authors: Brubach Howard F. , Altland Paul D. 
Published: December 2017

The construction and operation of a chamber with positive (up to 500 psi) or negative (simulated altitude to 50,000 ft) pressure with small animals is described. Special regulatory and safety features for low-pressure studies include a barometer connected electrically with a ventilation valve which automatically prevents a pressure drop (less than 100 ft simulated altitude) below a predetermined point, and a valve to prevent backflow of water from the vacuum pump in case of power or equipment failure. A means of controlling the temperature within 1 C is described. For low-pressure work, the chamber is also provided with clear Lucite doors, one of which opens automatically when the pressure is equalized. altitude; anoxia; aviation medicine; decompression; atmospheric pressure Submitted on March 26, 1963
Alveolar-arterial oxygen gradient in Andean natives at high altitude
Authors: Kreuzer F. , Tenney S. M. , Mithoefer J. C. , Remmers J. 
Published: December 2017

The A-a Do2 (alveolar-arterial oxygen tension difference) was determined at three levels of oxygenation in three groups of subjects: 1) normal persons at sea level, 2) normal Andean natives at high altitude, 3) Andean natives with chronic mountain sickness. The values of A-a Do2 in the Andean natives were uniformly higher than in normal sea-level residents at all levels of oxygenation. These findings were accentuated in patients with chronic mountain sickness. It is concluded that there is no decrease in diffusion barrier for oxygen, and there may be increased veno-arterial shunting in the lung and wider distribution of ventilation-perfusion ratios in the high-altitude residents than in normal subjects at sea level; and that part, at least, of the condition of chronic mountain sickness is an accentuation of these changes. tissue hypoxia; acclimatization; chronic mountain sickness; secondary polycythemia; pulmonary O2 diffusion barrier; pulmonary veno-arterial shunt; pulmonary ventilation perfusion ratio Submitted on April 3, 1963