bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heat reactions of some Bantu tribesmen in southern Africa
Authors: Wyndham C. H. , Strydom N. B. , Williams C. G. , Morrison J. F. , Bredell G. A. G. , Peter J. , Van Graan C. H. , Holdsworth L. D. , Van Rensburg A. J. , Munro A. 
Published: December 2017

Samples of 20 Bantu each from various tribes in southern Africa have been subjected in the late summer in Johannesburg to the established “standard heat-stress test” and were compared with a sample of mixed Bantu, studied in Johannesburg in the late winter. The mean rectal temperatures of the summer group were significantly lower than the mean of the winter group. Heart rates and sweat rates were not different. Intertribal comparisons revealed no significant differences in resting values or in heat reactions. An outstanding feature was that only 3 men of the 120 unacclimatized Bantu reached a rectal temperature of 104 F, and only one collapsed (this is 3% compared to the 50% of Caucasians who did not complete the test). No distinctions can be made between these Bantu tribes in their states of acclimatization in spite of the fact that some came from temperate and others from subtropical regions. The range of climates in the tribal territories is, however, small. Expressed as basic effective temperatures, the January climates—a hot, summer month—vary from 71 to 79 F in these different region physiological reactions of Bantu tribesmen Submitted on September 17, 1963
Specific gravity of human subjects by air displacement and helium dilution
Authors: Hix V. M. , Pearson A. M. , Reineke E. P. 
Published: December 2017

Body volumes for 24 men and 24 women were determined using both the air-displacement and helium-dilution procedures. Specific gravity values were calculated and computed. The two methods of determining body volume showed extremely good agreement, with a correlation of 0.99 for both men and women. The correlation between specific gravity values was 0.96 for men and 0.91 for women. Thus, the over-all agreement between the two methods was relatively good, although the mean deviation was relatively large. The major sources of error for the helium-dilution procedure appeared to be due to changes in temperature, to irregular accumulation of carbon dioxide within the chamber, and to difficulty in setting the current to the thermal conductivity cell at precisely the same level. The major sources of error in the air-displacement method seemed to be due to changes in temperature, changes in relative humidity, and lack of precision in making pressure readings on the manometer. body composition; body volume by air displacement; body volume by helium dilution; specific gravity measurements Submitted on October 28, 1963
Hypoxic pulmonary hypertension of the calf with denervation of the lungs
Authors: Reeves John T. , Leathers James E. 
Published: December 2017

Transection of the spinal cord at the level of C2, spinal anesthesia, and/or bilateral vagotomy were done in 11 healthy young male calves. These procedures did not block the pulmonary arterial pressure rise with 12 or 9% oxygen, but they did block the increase in heart rate and systemic arterial pressure which accompanied hypoxia when the central nervous system was intact. The central nervous system, therefore, appeared to mediate the response to acute hypoxia of the systemic circulation, but not the pulmonary arterial pressure rise. hypoxia; pulmonary circulation; spinal cord section; spinal anesthesia; vagotomy Submitted on February 19, 1964
Effect of tubocurarine on respiratory and nonrespiratory muscle power in man
Authors: Johansen Sophus H. , J⊘rgensen Mogens , Molbech S. 
Published: December 2017

On human volunteers the degree of muscular depression in respiratory power and handgrip strength was determined when ability to raise the head was almost or completely abolished by (+) tubocurarine. In one series the course of restitution after maximal depression of head lift, handgrip, maximal inspiratory and expiratory flows were compared. In the second series measurements of maximal inspiratory and expiratory pressures replaced those of maximal flows. In all experiments the respiratory functions were consistently much less affected than head lift and handgrip. Of the two last mentioned the power in head lift was always most affected. The results suggest that, in normal man, respiratory muscle power is relatively well preserved when curarization is carried to the point where the ability to raise the head is nearly abolished and the strength in handgrip is severely retarded. effect on head lift Submitted on November 15, 1963
Reactions to heat of Arabs and Caucasians
Authors: Wyndham C. H. , Metz B. , Munro A. 
Published: December 2017

The physiological reactions to heat of samples of French servicemen and of Arabs in the Sahara Desert, were compared with those of South African Caucasians. Both Sahara groups displayed evidence of partial acclimatization; their reactions were better than those of the unacclimatized; but not as good as those of the acclimatized South African Caucasians. The French servicemen were slightly better acclimatized than the Arabs; they had lower rectal temperatures and heart rates, and higher sweat rates. This paradoxical finding indicates that the Arabs, although their ancestors have lived in the Sahara Desert for some centuries, display no greater adaptation to hot conditions than recent Caucasian inhabitants. The morphology of the Arab gives him a greater surface area: mass ratio than the Caucasian. This favors heat loss, but under the test conditions the Arabs had no apparent advantage in physiological reactions. The differences in morphology of the Arab and Caucasian appear to be related more to their nutritional state and physical activity levels than to any structural adaptation to heat. acclimatization to heat in Sahara Desert; adaptation to heat of Arabs; Caucasians and Arabs in Sahara Desert; heat reactions in the desert; morphology and adaptation to heat Submitted on February 28, 1964
Effect of O2 at high ambient pressure on blood flow and O2 consumption of the kidney
Authors: Rennie D. W. , Knox F. G. 
Published: December 2017

Renal blood flow of chloralosed dogs, measured while they breathed 100% O2 at ambient pressures of 1, 2, 3, and 4 atm abs (OHP), declined exponentially as an inverse function of PiOO2 until at 4 atm O2 it was 57% of control. Denervating the kidney did not affect the response, the mechanism of which remains unknown. Mean arterial blood pressure increased to 112% of control and heart rate decreased to 60% of control as O2 pressure increased from 1 to 3 atm abs, suggesting a generalized systemic vasoconstriction in which the kidney participated. We estimate that the measured decrease in renal blood flow during OHP would account for approximately 20% of the total decrease in peripheral blood flow. Renal O2 consumption was not affected by OHP. This can be accounted for in terms of a constant filtered and reabsorbed sodium load Note: (With the Technical Assistance of D. R. Wilson) hyperbaric oxygenation; kidney circulation; environmental pressure Submitted on February 20, 1964
Changes in concentration of gases in the rubber bladders of Max-Planck respirometers
Authors: Rahaman M. M. , Durnin J. V. G. A. 
Published: December 2017

Changes of concentration of CO2 and O2 through rubber bladders were determined by a) exposing the bladders to atmospheric air, b) putting them into polythene bags and inflating the bags by 1) normal expired air and 2) by the same gas mixture as inside the bladders. Two different gas mixtures (of similar percentage composition to that of expired air samples obtained during light and moderate exercise) were used. The rate of diffusion was found to depend on the partial pressure gradient across the rubber wall and the type of gas. The higher the partial pressure gradient, the more rapid was the diffusion, and CO2 diffused at a higher rate than O2. Such a simple procedure as putting the bladders into polythene bags and inflating the bags by the operator's own expired air was found to reduce the change of concentration considerably. A correction can be utilized to obtain a more accurate gaseous percentage composition if there is a delay between the experiment and the gas analysis. carbon dioxide; oxygen; diffusion of gases; indirect calorimetry Submitted on October 17, 1963
Physiological effects of active and passive exercise
Authors: Benjamin F. B. , Peyser L. 
Published: December 2017

A comparison of the physiological effects of active and passive exercise was accomplished using two methods. In the first series of experiments, the exercise was held constant. In the second method, an attempt to match oxygen consumption was employed. The results, evaluated in view of preceding investigations in the same area, indicate that: 1) Passive exercise inincreases ventilation in excess of the metabolic need. The greater ventilation increases the ventilating equivalent and lowers the end-tidal Pco2, possibly causing respiratory alkalemia. 2) The increase in ventilation accompanying passive exercise does not produce a corresponding increase in heart rate. 3) Passive exercise increases heat production beyond the level indicated by oxygen consumption. These findings support the concept of a temperature factor being involved in the hyperventilation of exercise. ventilation equivalent in exercise; oxygen consumption in exercise; body temperature in exercise Submitted on March 25, 1964
Changes in tone of limb veins during supine exercise
Authors: Bevegård B. Sture , Shepherd John T. 
Published: December 2017

Normal subjects have been studied to assess the response of the capacitance vessels in the forearm during supine leg exercise. Measurements were made of changes in forearm volume (strain-gauge and water-filled plethysmographs) at a given pressure in the large forearm veins, of changes in pressure in the forearm veins with the circulation to the forearm arrested and in “isolated” vein segments. The results were consistent and demonstrated that exercise with a work load of 270–810 kg/min caused constriction of forearm capacitance vessels via the sympathetic nerves proportional to the severity of the exercise. Venoconstriction also occurred in the hand, and in the calf during arm exercise. Local exercise of the forearm muscles during supine leg exercise, which increased forearm blood flow by dilating the resistance vessels, did not prevent the increase in venous tone in the forearm. Thus a reflex increase in tone in the limb veins, both in the exercising and in the nonexercising parts, contributes to the cardiovascular adaptation to exercise. venoconstriction in exercising and nonexercising limbs; reflex venoconstriction with exercise graded to severity of work; reflex venoconstriction with exercise mediated through sympathetic nerves Submitted on June 15, 1964
Variations in cardiac output associated with hemoglobin levels in anesthetized sheep
Authors: Halmagyi D. F. J. , Starzecki B. , Horner G. J. 
Published: December 2017

Hemoglobin levels in sheep was found to be related inversely to the logarithm of cardiac index and directly to the calculated systemic and pulmonary arterial resistances over a wide spectrum of hemoglobin concentrations including the normal range. It appeared to be based on changes in blood viscosity produced by a varying red cell concentration. The continuous adjustment of hemoglobin levels and cardiac output may account for the variability of cardiac output values in normal laboratory animals and may represent a mechanism maintaining oxygen delivery to the tissues in the presence of changing oxygen carrying capacity. blood viscosity; vascular resistance; oxygen carrying capacity Submitted on May 15, 1964
Initial responses to added viscous resistance to inspiration in dogs
Authors: Wiley Ronald L. , Zechman Fred W. 
Published: December 2017

Respiratory mechanics and diaphragm electromyograms in six anesthetized dogs were studied to determine the immediate nonchemical responses to three levels of added airflow resistance to inspiration. Inspiratory time, intrathoracic pressure amplitude, diaphragm activity, and inspiratory work all increased in the first breath with added resistance. The adjustments to added viscous resistance are interpreted as indicating an immediate active response which tends to maintain an adequate tidal volume. Even though Vt decreased with added resistance, the area under the inspiratory volume curve was unaltered on the first resistance breath. Thus, during the initial response, inspiratory duration may depend primarily upon the accumulated or summated information related to change in volume. Work done on the lung and apparatus was greater with added resistance. The increase resulted from the increased inspiratory time rather than change in rate at which work developed during the inspiration. After two to three breaths on resistance the inspiratory work rate began to increase, probably reflecting the addition of secondary chemical drive. airflow resistance; diaphragm electromyogram; respiratory control Submitted on February 14, 1964
Bronchospirometric studies of lung volumes, ventilation/perfusion ratios and diffusion
Authors: Cree E. M. , Rasmussen H. K. , Wright F. , Curtis J. K. 
Published: December 2017

Bilateral bronchospirometric nitrogen washout studies were used for the first time to calculate ventilation/perfusion ratios for the well and poorly ventilated areas in individual lungs. Results were compared with washout studies on both lungs measured together. Data suitable for analysis were obtained from seven patients with chronic lung disease. It was demonstrated that this technique for determining simultaneous ventilation/perfusion ratios for each lung gave accurate and detailed physiological changes. Comparison of the sum of average values for pulmonary capillary blood flow when both lungs were measured together by the same nitrogen washout technique showed a variation within the accepted 10% error for cardiac output. Diffusion for the separate lungs, measured by the carbon monoxide breath-holding method, gave values which correlated with lung volumes. bronchospirometry; nitrogen washout; diffusing capacity Submitted on November 22, 1963
Hemolysis induced by a Bellofram blood pump; chronic in vitro evaluation
Authors: Liddle Harold V. , Reynolds Harold C. , Carlson Warner W. 
Published: December 2017

In the application of extracorporeal pumping systems to chronic assisted circulation, hemolysis may be an important factor. A reciprocating pump utilizing rolling diaphragms has been tested for production of free plasma hemoglobin. In a recirculating system, 1,500 ml of freshly drawn heparinized dog blood was circulated at a flow rate of 3,000 ml/min against pressures of 100, 200, and 300 mm Hg for from 1 to 24 hr. Hemolysis was determined by a modified benzidine method. Recirculation for 1 hr against a height of 142 cm produced 3.6 mg/100 ml, 1.8 mg/100 ml, and 2.4 mg/100 ml free plasma hemoglobin, respectively, for hemolysis indices of 0.001- 0.0013. When the same priming volume was recirculated at 3,000 ml/min and 300 mm Hg pressure for 24 hr, the average hourly rate of free hemoglobin accumulation was 0.5 mg/100 ml, an index of 0.0006. These rates of hemolysis are comparable to the estimated normal human production of free plasma hemoglobin. The extremely low rate of hemolysis produced by this pump is related to the noncompressive action of the rolling diaphragms and flap valves. The characteristics of its performance make this pump ideally suited to chronic perfusion. extracorporeal pump; assisted circulation; rolling diaphragm; reciprocating pump Submitted on June 18, 1964
Free fatty acid responses to tilting after water immersion
Authors: Goldman Jack K. 
Published: December 2017

Water immersion is accompanied by decreased urinary excretion of noradrenaline and is followed by orthostatic intolerance. The latter has been postulated to result from impaired noradrenaline metabolism. Such an impairment would produce, in addition, a diminished rise in plasma free fatty acids in response to tilting. This response was measured in normals after office control, water immersion and exposure to a thermal environment identical to that found in the immersion facility. The plasma free fatty acid response to a tilt is impaired after water immersion as would be expected if sympathetic nervous system dysfunction is involved in postimmersion orthostatic intolerance. hypodynamics; orthostatic intolerance; orthostasis sympathetic nervous system; noradrenaline; cathecholamines; simulated o G Submitted on July 10, 1964
Initial hemodynamic responses to mild exercise in trained dogs
Authors: Smulyan Harold , Cuddy Richard P. , Vincent William A. , Kashemsant Udomporn , Eich Robert H. 
Published: December 2017

The transient changes in cardiac output at the onset of mild exercise were measured in dogs trained to walk on a treadmill. Cardiac output was obtained using a krypton 85 infusion method, which permitted frequent determinations of flow. The first go sec of exercise were marked by a prompt rise and overshoot of heart rate and cardiac output, whereas increases in stroke volume occurred later after the onset of exercise, and to a lesser extent than heart rate. At rest, the right atrium was electrically driven at rates slightly faster than heart rates attained spontaneously with exercise and the studies repeated. Changes in cardiac output with exercise were similar to those in unpaced animals, but when the heart rate was fixed stroke volume increased immediately. These studies show a consistent rise in heart rate and cardiac output in the initial reaction to exercise, but when the prompt rise in heart rate was prevented by pacing from the right atrium, increases in stroke volume provided a comparable response in cardiac output. krypton 85; cardiac output; stroke volume; pacing of heart; oxygen consumption Submitted on September 23, 1964
Continuous sampling of arterial blood of unanesthetized animals
Authors: Hamilton Robert W. 
Published: December 2017

Implanted arterial catheters permit recording, sampling, and injecting when used in unanesthetized and undisturbed dogs or cats. The catheters are made of silicone rubber tubing fitted to plastic Luer hubs which terminate in resealing rubber serum caps. The catheters are inserted into the descending aorta via the carotid artery and are brought out through the skin on the back of the neck. Results indicate that they can be expected to function for several weeks. Note: (With the Technical Assistance of Robert L. Dauber and F. Richard Darrow) catheters, chronic; catheters, implanted; silicone rubber tubing Submitted on July 13, 1964
A system for providing surgical anesthesia for germfree rodents
Authors: Carter Darryl , Einheber Albert 
Published: December 2017

A system which has been successfully used to provide anesthesia for experimental surgical procedures on germfree rodents within a germfree surgical isolator is described. The preselected air-halothane mixture is sterilized by passage through spun-glass filters. A small Lucite chamber and a nose cone allow induction and maintenance of the halothane anesthesia within the isolator. The system has provided a safe, reproducible anesthesia from which recovery is brief and from which there is no explosion hazard. germfree animal techniques; halothane anesthesia Submitted on October 15, 1964
Treadmill for small laboratory animals
Authors: Andrews Robert James 
Published: December 2017

A treadmill for exercising small laboratory animals is described. Belt speed can be varied in steps from 13 to 70 ft/min; inclination can be varied from 0 to 160. The apparatus can be locally constructed of surplus laboratory materials and scrap for an estimated cost of $300. It is being satisfactorily used by the Physiology Division of the Naval Medical Field Research Laboratory, Camp Lejeune, North Carolina for biochemical studies utilizing white rats. small animal exerciser; biochemical studies; metabolism studies Submitted on August 24, 1964
Short-latency human evoked responses to clicks
Authors: Mast Truman E. 
Published: December 2017

The human average evoked response to clicks, recorded from almost any position on the scalp, shows a characteristic short-latency component with its peak at 30 msec. These responses are probably composite, originating partly from muscle and partly from brain. The response recorded from parietal (Pl) to vertex (Cz) differs significantly from a known muscular response from the inion. The 30-msec component from inion is markedly enhanced by contraction of the posterior neck muscles, while that from Pl-Cz is little affected. The two responses differ in their relations of amplitude to stimulus intensity. The Pl-Cz response also differs from temporalis and frontalis muscle responses. muscle response to clicks; sources of evoked responses Submitted on October 15, 1964
Storage media for rabbit ova
Authors: Hafez E. S. E. 
Published: December 2017

Rabbit ova were stored at 10 or 20 C for 2—14 days. Basic storage media contained: a) 1 or 7% gelatine, b) 7% gelatine and antibiotics, c) 2, 5, or 7% glycerol, d) basic medium but nitrogen atmosphere and storage at 10 or 20C, e) previously frozen serum, f) reconstituted “freeze-dried” serum, g) blastocyst or allantoic fluid, h) egg yolk or egg white, or i) tranquilizer. Stored ova were transferred to appropriate recipients which were laparotomized to measure the implantation rate, then killed to measure embryonic survival. After storage in gelatine media containing 7% gelatine, the rate of implantation was 53% after storage for 7 days and gradually declined until it reached 3% after 14 days of storage. Survival time of ova during storage tended to be prolonged in gelled media, but the addition of antibiotics did not prolong survival time. A concentration of 5% glycerol had no significant effect on ova survival, but the addition of 7% glycerol was deleterious. At 10 C, but not at 20 C, the presence of nitrogen had a deleterious effect on storage of ova. Fresh blood serum could be substituted by: serum previously frozen, reconstituted freeze-dried serum, blastocyst fluid, or egg yolk citrate. Ova did not survive when stored in egg white with Tyrode solution. embryology; antibiotics; implantation; embryos Submitted on March 23, 1964
Gradational step tests for assessing work capacity
Authors: Nagle Francis J. , Balke Bruno , Naughton John P. 
Published: December 2017

The feasibility of a gradational step test for the assessment of work capacity was investigated. A device was constructed on which the level of a stepping platform could be raised between 2.0 and 50 cm as subjects continued work at a prescribed stepping rate. Two test procedures applicable to individuals who vary in their state of health from that of a chronically ill patient to a trained athlete are described. Sixty men performed experiments to establish the minute-by-minute metabolic costs of the work in the two tests. The oxygen expenditures ranged from 12.9 ± 1.2 to 40.8 ± 3.5 ml/min per kg in the 30/min step test and from 10.7 ± 1.1 to 28.8 ± 1.3 ml/min per kg in the 24/min step test. The procedures are well suited for measuring various physiological parameters during stepping and for establishing physiological working limits. The oxygen costs of the “negative” and “positive” work components in stepping were determined. The cost of negative work was approximately one-third of the positive work. An equation was derived for predicting the metabolic costs of stepping at various rates and platform levels. Comparisons of predicted and measured oxygen intake values for the 30-step and 24-step tests approximated one another at all levels of energy expenditure. energy expenditure stepping; cardiorespiratory responses to exercise; work in stepping; negative work; positive work; physical fitness tests Submitted on August 7, 1964