bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acid-base balance and blood and urine electrolytes of man during acclimatization to CO2
Authors: Schaefer K. E. , Nichols G. , Carey C. R. 
Published: December 2017

Acid-base balance regulation and changes in electrolyte metabolism have been studied in 20 subjects exposed to 1.5% CO2 over a period of 42 days with control periods preceding and subsequent to exposure. During exposure to CO2 a slight uncompensated respiratory acidosis was present during the first 23 days followed by a compensated respiratory acidosis. Deacclimatization was incomplete, even after 4 weeks of recovery on air. Arterial CO2 tension increased 5 mm Hg during exposure and remained at this elevated level during the first 9 days of recovery on air. In chronic respiratory acidosis the concentration of chloride in the red cells and in plasma remains practically normal, indicating that the chloride shift does not operate. Cation exchange was observed under these conditions. Sodium increased while potassium showed an approximately equivalent decrease. Sodium and potassium balance studies indicated that only sodium exhibits a pattern paralleling the two phases of acid-base balance regulation, retention being followed by increased excretion. Body weight was maintained throughout the experiment in spite of a 24–30% reduction in food intake. mild respiratory acidosis and compensation; 1.5% CO2 exposure and recovery; arterial pCO2, chloride shift, and cation exchange; sodium and potassium excretion; sodium potassium and nitrogen balance; acid-base regulation in chronic hypercapnia; time course in acid-base regulations during chronic exposure to low concentration of CO2; acclimatization and deacclimatization to low concentration of CO2 Submitted on July 22, 1963
Tracheostomy and respiratory dead space in emphysema
Authors: Froeb Herman F. , Kim Byong M. 
Published: December 2017

Acute experimentation to judge the effects of reduction of dead space with tracheostomy breathing was performed on four subjects with lower airway obstruction (bronchitis and emphysema) and on two subjects with upper airway obstruction (carcinoma of the larynx and tracheal stenosis). With tracheostomy breathing, the reduction in dead space led to a decrease in minute ventilation except in the two patients with upper airway obstruction. Alveolar ventilation decreased except when alveolar hypoventilation was present to start with. There was no change or an increase in Pacoco2 and H+ in the subjects with lower airway obstruction and small increases in arterial oxygen saturation and Paoo2 occurred. A decrease in Pacoco2 and H+ occurred in one of two patients with upper airway obstruction. Reduction of dead space per se with tracheostomy breathing brings about small changes in alveolar ventilation and gas exchange in the lungs of patients with chronic bronchitis and emphysema. Note:(With the Technical Assistance of Roy Engstrom, Mabel Pearson, and Tom Purcell) physiological dead space and tracheostomy; arterial blood gases with tracheostomy breathing; tracheostomy versus mouth breathing; emphysema and tracheostomy breathing Submitted on February 11, 1963
Effect of simulated breath sounds on ventilation
Authors: Williams M. Henry , Kane Cecile 
Published: December 2017

When normal subjects listened to simulated breath sounds while breathing at their natural respiratory frequency there was a significant decrease of alveolar Pco2. The alveolar Pco2 did not fall further when these subjects listened to the simulator and breathed slowly, but when they breathed with the simulator at a very rapid frequency there was further fall of the PaCOCO2. When patients with chronic obstructive pulmonary disease listened to simulated breath sounds while breathing at their natural respiratory frequency there was a decrease of arterial Pco2 which fell further when the subjects breathed with the simulator at a slow respiratory rate. breathing, effect of auditory stimuli on; breathing rate and pulmonary function on chronic obstructive pulmonary disease; alveolar ventilation and auditory respiratory stimuli; respiratory frequency and ventilation Submitted on July 12, 1963
Psychological and physiological responses to raised body temperature
Authors: Wilkinson R. T. , Fox R. H. , Goldsmith R. , Hampton I. F. G. , Lewis H. E. 
Published: December 2017

The performance of 12 male volunteers in an adding test and in a test requiring prolonged vigilance was measured at normal body temperature and while temperature was maintained at 37.3, 37.9, and 38.5 C. Each subject was measured at each level of body temperature on four occasions. Both the extent and the direction of the effect on performance varied with 1) the task being carried out, and 2) the degree of temperature elevation. Compared with performance at normal temperatures, the ability to add was impaired and vigilance was improved at 38.5 C. At 37.3 C, on the other hand, smaller changes reflected in general an improvement in adding and an impairment of vigilance. As a result of the repeated sessions of controlled hyperthermia, the subjects became heat acclimatized but there was no corresponding improvement in performance at raised body temperature, indicating the absence of short-term adaptation of the central nervous system functions tested to repeated elevations of body temperature. hyperthermia; vigilance and addition performance in hyperthermia; heat acclimatization male Caucasians; psychomotor performance; heat tolerance; artificial acclimatization Submitted on August 15, 1963
Effects of central stimulants on onset of diaphragm activity during breath holding
Authors: Agostoni E. , Sant'Ambrogio G. , Mognoni P. 
Published: December 2017

The effect of d-methylamphetamine, caffeine, and analeptics on the alveolar Pco2 during spontaneous breathing and at the onset of diaphragm activity during breath holding has been studied. After d-methylamphetamine the value of alveolar Pco2 at the onset of diaphragm activity, as well as at the breaking point, is significantly increased, while the ventilation-alveolar Pco2 relationship is not changed. After caffeine the value of the alveolar Pco2 at the onset of diaphragm activity, as well as at the breaking point, is significantly decreased and the ventilation-alveolar Pco2 relationship is significantly shifted to a lower Pco2. The value of alveolar Pco2 at onset of diaphragm activity is significantly decreased by prethcamide, increased by pentylenetetrazol, and not affected by dimefline. The ventilation-alveolar Pco2 relationship was not changed by such analeptics. These data, together with those previously obtained on hypoxia, suggest that factors changing the ventilation-alveolar Pco2 relationship also affect the onset of diaphragm activity, while the onset of diaphragm activity can be changed without affecting the ventilatory response to CO2. effect of analeptics on breath holding and on CO2 response curve; breaking point of breath holding; effect of caffeine on breath holding and on CO2 response curve; effect of d-methylamphetamine on breath holding and on CO2 response curve; ventilation-alveolar Pco2 relationship Submitted on July 5, 1963
Effect of atropine and reserpine on pulmonary diffusing capacity during exercise in man
Authors: Krumholz Richard A. , Ross Joseph C. 
Published: December 2017

Pulmonary diffusing capacity increases with exercise. The rapidity of this increase after the onset of exercise and factors which may alter it, i.e. atropine (2.0 mg i.v.) and reserpine (0.5 mg/day p.o. for 7 days), were investigated. Breath-holding Dl determinations were made before exercise began, at 0–10 sec of exercise, after 1, 2, and 3 min of exercise, and 3 min after the end of exercise. Dl was already strikingly increased at 0–10 sec of exercise, although further increases occurred during the 3-min exercise period. Following atropine administration in nine subjects the immediate rise in Dl at 0–10 sec of exercise was significantly reduced (P < 0.01), but the increases with further exercise were not significantly altered. After the reserpine administration in six subjects, the 0–10 sec exercise Dl values tended to be lower, but not to a significance level of <.05, and there was a tendency toward lower Dl values throughout the 3-min exercise period. This study suggests, then, that the immediate and the later increases in Dl with exercise are produced by two different mechanisms. pulmonary diffusion; pulmonary diffusion in exercise; mechanism for increased diffusion in exercise; pulmonary capillary bed Submitted on September 23, 1963
Environmental stresses and femoral arterial blood flow
Authors: Boon D. J. , Marotta S. F. 
Published: December 2017

Femoral arterial blood flow and related cardiopulmonary parameters were ascertained in 95 anesthetized dogs during exposure to heat, cold, altitude, hypoxia at two different times, and various combinations of these environments. Cold (1 C) and decompression (17,300 ft) without hypoxia at room temperature (24 C) each depressed arterial blood flow significantly the same amount, while the combination of decompression and cold caused a significant depression in flow less than either acting alone. Heat (38 C) alone produced slight increases in arterial pressure and heart rate; however, heat in combination with altitude depressed the flow less than did altitude alone. Hypoxia (Po2 75 mm Hg), whether from decompression or breathing 10% O2 at ground level, increased blood flow while depressing femoral vascular resistance in all animals in cold, hot, or room temperatures. The greatest hypoxic increases in blood flow were noted immediately after decompression both at 24 and 38 C, while the smallest increase was noted with hypoxic exposure during the second period at a cold, simulated altitude. circulation and stress Submitted on June 19, 1963
Work tolerance: age and altitude
Authors: Dill D. B. , Robinson S. , Balke B. , Newton J. L. 
Published: December 2017

The work capacity at sea level and high altitude has been measured on nine men, five of whom had taken part in similar studies at high altitudes from 18 to 33 years earlier. Except for a few measurements on the treadmill at sea level each subject rode the bicycle ergometer; the brakeload was increased minute-by-minute until his limit was reached. The maximum capacity for oxygen intake declined with age both at high altitude and at sea level. Individual responses varied greatly: the most fit individual, age 54, had about as great an oxygen intake on the ergometer at Pb 455 mm Hg as had a man one-half his age at sea level. After 5 or 6 weeks of acclimatization a man of 71 attained at Pb 485 a greater oxygen intake per minute and per kilogram than that of a man of 27. At that barometric pressure the limiting oxygen intake on the bicycle ergometer may be only one-half of the sea-level value 2 or 3 days after arrival; after 4–6 weeks it may range from two-thirds to five-sixths of the sea-level value. adaptation to altitude; altitude and heart rate; altitude and maximum O2 intake; altitude and respiratory volume Submitted on November 4, 1963
Physiological reactions of Caucasian and Bantu males in acute exposure to cold
Authors: Wyndham C. H. , Ward J. S. , Strydom N. B. , Morrison J. F. , Williams C. G. , Bredell G. A. G. , Peter J. , Von Rahden M. J. E. , Holdsworth L. D. , Van Graan C. H. , Van Rensburg A. J. , Munro A. 
Published: December 2017

Eleven men per sample of Caucasian and Bantu males were exposed for 2 hr in a climatic chamber at various air temperatures ranging from 5 to 27 C, and a wind velocity of 80–100 ft/min. When expressed per square meter surface area the metabolism of the Bantu was greater in the range above 18 C and below 6 C. Average skin temperatures were similar for both groups, but between 27 and 17 C the toe and finger temperatures of the Caucasians were significantly higher than that of the Bantu—the difference at 27 C being 5 C for the fingers and 3.6 C for the toes. Rectal temperatures of both groups were similar between 27 and 17 C. With the rectal temperatures at 27 C air temperature as the criterion, it was found that as the air temperatures decreased below the 27–17 C range the rectal temperatures of the Bantu fell linearly, while the rectal temperatures of the Caucasians rose steadily. There is no doubt that in certain ranges of air temperatures there are significant differences between the cold reactions of Caucasians and the Bantu. cold adaptation; ethnic differences in response to cold; metabolic and body temperature reactions to cold; metabolic response to body temperature; metabolic reactions of ethnic groups Submitted on July 15, 1963
Turnover rate and oxidation of different free fatty acids in man during exercise
Authors: Havel Richard J. , Carlson Lars A. , Ekelund Lars-Göran , Holmgren Alf 
Published: December 2017

Palmitate-9, 10-H3 has been infused intravenously at a constant rate together with various C14-labeled fatty acids in healthy subjects at rest and during exercise. No significant differences in the rates of fractional turnover were found between H3-labeled palmitate and C14-labeled palmitate or oleate. Retention of a considerably larger fraction of C14-labeled linoleate in the blood plasma precluded accurate assessment of its fractional turnover rate. The rates of oxidation of palmitate-I-C14, palmitate-U-C14, oleate-I-C14, and linoleate-I-C14 during exercise were similar. The relative abundance of palmitate, oleate, and linoleate in the free fatty acids of plasma changed little during exercise. It is concluded that palmitate-I-C14 is a valid tracer for measuring the turnover rate and oxidation of at least three-fourths of circulating free fatty acids under the conditions of study. Recycling of radioactivity in triglyceride fatty acids of plasma was similar for H3-labeled palmitate and C14-labeled palmitate and oleate, both at rest and during exercise. The plasma concentration of glycerol increased promptly with exercise. Changes in its concentration closely followed those in the turnover rate of free fatty acids, but were of greater magnitude. plasma glycerol during exercise; plasma triglycerides, formation from different FFA; respiratory quotient during exercise Submitted on October 4, 1963
Expiratory activity of the abdominal muscles in man during general anesthesia
Authors: Freund Felix , Roos Albert , Dodd Robert B. 
Published: December 2017

The integrated electromyogram was recorded from the lateral abdominal muscles in 24 young normal male volunteers in the supine position, both during consciousness and during light general anesthesia, produced by 50 or 80% N2O in O2, or by 0.5–2% halothane in air after thiopental. No activity was observed during quiet breathing in the conscious state, but throughout anesthesia all subjects exhibited expiratory muscle activity. Activity gradually subsided as consciousness was regained, but suddenly disappeared on vocal arousal. Expiratory intragastric pressure increased up to 7.6 cm H2O above control. End-expiratory Pco2, minute volume, and airway resistance (interrupter technique) did not change significantly. Forced inflation during inspiration, maintained for five to six respiratory cycles, depressed activity during the first three to four cycles; subsequent deflation restored activity. Inflation during expiration immediately reduced activity. Mechanisms that might lead to recruitment of the expiratory muscles are considered. Expiratory activity frequently observed in experimental animals might, at least in part, be due to anesthesia, and thus not represent the breathing pattern during consciousness. abdominal electromyogram; respiratory reflexes Submitted on November 4, 1963
Influence of carbon dioxide on pulmonary vasculature
Authors: Hyde R. W. , Lawson W. H. , Forster R. E. 
Published: December 2017

The single-breath CO diffusing capacity (Dl) and pulmonary vascular resistance (PVR) were measured in isolated perfused cat lungs exposed to varying concentrations of CO2. Ventilation of the lungs with 5–10% CO2 produced a significant rise in D1 and PVR compared to contro1 values breathing room air. Perfusion of five lungs with blood equilibrated with 5–10% CO2 while breathing room air produced a significant rise in PVR but inconsistent changes in D1. When the direction of perfusion was reversed so that blood entered the lungs through the pulmonary veins, ventilation with 7.5–10% CO2 increased both D1 and PVR while perfusion with blood equilibrated with 10% CO2 only increased PVR. These findings indicate: 1) arteries and veins can constrict independently when directly exposed to elevated CO2 tensions; and 2) if the capillaries and downstream vessels are exposed to elevated CO2 tensions, D1 is increased. A likely mechanism is that constriction downstream from the capillaries produces a rise in their transmural pressure, which in turn causes an increase in capillary blood volume. Among alternative explanations for the change in D1 is the possibility that CO2 increases the speed of the uptake of CO by erythrocytes. Submitted on June 18, 1963
A new type of syringe holder for performance of indicator-dilution curves
Authors: Benson Robert W. , Krovetz L. Jerome , Schiebler Gerold L. 
Published: December 2017

A new type of syringe holder, simple and rugged, has been designed to combine a constant volume syringe with an electrical time marker initiator. The latter allows a precise determination of the appearance time of an indicator-dilution curve. appearance time Submitted on March 2, 1964
Development and use of a solenoid-powered, spring-driven heart substitution pump
Authors: Holt J. P. , Drury Ralph , Kines Helga 
Published: December 2017

A single solenoid, variable rate pump, whose right and left chamber end-systolic volumes are determined by the levels of the pulmonary and aortic end-systolic pressures, respectively, is described. In studies in a model of the circulation, the pump simulates to a high degree the functioning of the mammalian heart; and in acute experiments on dogs it has successfully replaced the heart for as long as 15 hr. It is suggested that with miniaturization the pump can be placed within the chest. artificial heart; circulation model Submitted on October 21, 1963
Cardiac output during exercise and anaerobic metabolism in man
Authors: Thomas H. D. , Boshell Buris , Gaos Carlos , Reeves T. J. 
Published: December 2017

The concentration time course of lactate, pyruvate, and excess lactate during 4 min of exercise and 30 min of recovery was studied in 20 patients with heart disease and in 8 normal subjects. The level of excess lactate accrued from the exercise was found to correlate well with the level of delta oxygen consumption in normal subjects ( r = .922). The cardiac output of the subjects with heart disease was considered in relation to the regression of cardiac output on oxygen consumption for normal subjects previously established by Donald (Clin. Sci. 14: 37–73, 1955). The patients with subnormal cardiac outputs during exercise had higher excess lactate values and lactate/pyruvate ratios than normal subjects and patients with normal cardiac outputs at similar levels of work. Normal subjects carrying out more severe work showed even higher concentration of excess lactate than did the patients with heart disease at lower work levels. The increase in excess lactate was maximal during the 2nd min of submaximal exercise. The rate of increase was progressively diminished during succeeding minutes. Note: (With the Assistance of James Carr and Wayne Vaughan) lactate; pyruvate; excess lactate Submitted on December 10, 1963
Sweetness produced electrically on the tongue and its relation to taste theories
Authors: Békésy G. Von 
Published: December 2017

Electrical stimulation of the tongue under controlled conditions produces pure sensations of the four basic tastes. These basic tastes correspond to four kinds of papillae which are distinguished by differences in their anatomical structures, their frequency response curves, and the times required for the buildup of sensation, but which all have about the same chronaxie. Although these findings do not favor the cluster theory of taste perception, adaptation experiments indicate that they do not disagree with the microelectrode recordings of nervous discharges of taste fibers in the chorda tympani. electrical taste; frequency response of the four specific taste buds; inhibition of taste sensations; interaction between taste buds; specific taste receptors; taste buds; taste units Submitted on March 2, 1964
Effect of diet, posture, and guanethidine on THH2Oc in hypertensive subjects
Authors: Ramos Oswaldo Luiz , Ajzen Horacio , Lima M. Cacilda 
Published: December 2017

Studies of renal function in four hypertensive patients under various conditions of diet, therapy, and position were undertaken in an effort to clarify their relationship to THH2Oc and to further illucidate the mechanism by which THH2Oc is altered. The results indicate that the decrease of THH2oc induced by a low-salt diet is not due to the concomitant decrease of glomerular filtration rate, clearance of sodium, or sodium load to the loop of Henle. Acute decrease of GFR by standing position is accompanied by a significant increase of THH2oc. It was also shown that the modification of ! occurred apparently independently of the variations in renal plasma flow. Finally it was not possible, in our patients, to detect the actual mechanism by which a low-salt diet decreased THH2oc. recumbent and standing position; normal diet; Na-deficient diet Submitted on August 8, 1963
Frequency response of electromagnetic flowmeters
Authors: Gessner Urs , Bergel Derek H. 
Published: December 2017

A comparison was made between hydraulic and electrical determination of the frequency response of two types of electromagnetic flowmeter. The output of the square-wave meter tested was reduced in amplitude by 10% at 7 cycles/sec; it lagged behind the input by approximately 4.5°/cycle per second. The output of the gated sine-wave meter was reduced by 10% at 24 cycles/sec and the phase lag was approximately 2.2°/cycle per second. No significant difference was detected between the results of either method of calibration. The frequency response of these instruments is determined by the characteristics of their electrical circuits. It is recommended that each user calibrate his own instrument; a simple method of electrical calibration is described. Since the frequency response of either meter is relatively poor, flow records obtained with them must be appropriately corrected. methods of calibration Submitted on March 9, 1964
Effect of embalming on the mechanical properties of beef bone
Authors: McElhaney James , Fogle John , Byars Edward , Weaver George 
Published: December 2017

Small tension and compression specimens were made from beef femurs and alternate specimens were embalmed. The stress-strain diagrams were then obtained using automatic recording equipment. From this diagram the modulus of elasticity, ultimate strength, and maximum strain to failure were determined. The hardness of all specimens was measured. A statistical evaluation of the data indicated that embalming causes a significant reduction (12%) in the ultimate compressive strength of beef bone, but only very slight reductions in ultimate tensile strength, maximum strain, and modulus of elasticity. The change in hardness was found to be insignificant. ultimate strength of beef bone; modulus of elasticity of beef bone; hardness of beef bone; tensile testing of beef bone; compressive testing of beef bone Submitted on October 1, 1963