bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy cost, fluid and electrolyte balance in subarctic survival situations
Authors: Rogers Terence A. , Setliff James A. , Klopping John C.
Published: December 2017

In two experiments a total of 12 men were subjected to 5 days of starvation under survival conditions in the winter subarctic. They wore flying clothing rated at 3.5 clo. The caloric cost, as calculated from oxygen consumption, was 2,300 kcal/m2 for the first day and 2,000 kcal/m2 for subsequent days at ambient temperatures of -30 C. At -10 C the cost of subsequent days fell to 1,500 kcal/m2. The subjects lost 8% of body weight but regained 5% body weight after 5 days refeeding on a barely maintenance diet. One-third of the original (8%) weight loss was due to an isotonic contraction of extracellular fluid. Changes in heart rate, pulse pressure, and hematocrit consistent with this fluid contraction were observed. Although the water intake did not exceed the 5-day urine volume (5 liters), the subjects did not experience thirst until after return to the warm.

Note:(With the Technical Assistance of William P. Esser and Kermitt R. Skrettingland)

caloric cost; cold exposure; electrolyte balance in starvation; fasting; fluid balance in starvation; IMP, integrating motor pneumotachograph; fat carbohydrate and protein catabolism in cold exposure and starvation; cold diuresis; sodium, potassium and acid-base balance in acute starvation

Submitted on June 3, 1963
Pulmonary alveolar-vascular reflex
Authors: Halmagyi D. F. J. , Colebatch H. J. H. , Starzecki B. , Horner G. J.
Published: December 2017

Lung mechanics and pulmonary circulation were studied in lightly anesthetized, spontaneously breathing, supine sheep. Aerosol atropine restored lung compliance (Cl) in animals after fluid inhalation. Ventilation-perfusion relationship was studied by comparing Cl and effective pulmonary capillary blood flow (Qe = 100 minus venous admixture in per cent of cardiac output). The relation between Cl and Qe in unpremedicated sheep before and after fluid inhalation suggested homeostatic redistribution of blood flow away from nonventilated areas. Compensation for nonventilated areas was enhanced by severe pulmonary hypertension and abolished by atropine or isoproterenol; vagotomy had no effect. Homeostasis therefore appears to depend on a local reflex response of the parasympathetic nervous system— “alveolar-vascular reflex.” Pulmonary hypertension of generalized alveolar hypoxia was a different reaction not blocked by atropine. Consistent with this analysis, an infusion of acetylcholine increased pulmonary arterial resistance. The increase in Cl which followed atropine or isoproterenol indicated that in addition to surface forces, smooth muscle contraction may result in closure of lung units.

lung mechanics and pulmonary circulation; fluid aspiration; atropine aerosol effect on lung compliance (Cl) after fluid inhalation; isoproterenol restored Cl; local homeostatic reflex response to pulmonary hypoxia; parasympathetic control of pulmonary ventilation; lung compliance (Cl) and effective pulmonary capillary flow (Qe) correlation

Submitted on March 25, 1963
Rheology and structure of blood suspensions
Authors: Charm S. E. , McComis W. , Kurland G.
Published: December 2017

A structural model developed for kaolin suspensions was applied to blood in order to determine the structure and strength of the red cell suspensions. The yield stress of red cell suspensions determined in settling experiments agreed with the yield stress determined from shear stress-shear rate information employing Casson's equation. Theoretical considerations indicate that the shear stress-shear rate curve for blood should approach a straight line. This was found to be true at shear rates above 40 sec-1. The slope of this line was predicted from calculations based on sedimentation experiments and a modified Einstein's equation. The data suggest that the curvature of the shear stress-shear rate plot at low shear rates is due to aggregates of cells which break down under increasing shear rate, resulting finally in individual flocs. It is suggested that a floc consists of one to four cells with adhering plasma. The aggregate was calculated to have twice as much plasma associated with it as does a floc. However, the size of the aggregate could not be determined since the number of flocs associated with an aggregate could not be determined.

shear stress-shear rate curve; red cell floc; red cell aggregate; sedimentation rate; blood viscosity and flow

Submitted on February 28, 1963
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
A technique for differential photoelectric plethysmography of brain and ear
Authors: Heck Albert F. , Hall Verlan R.
Published: December 2017

A technique for implantation and apparatus for obtaining a circulatory pulse volume wave from the surface of the cerebral cortex of animals in both acute and chronic experimental situations are described. Fiber optic light guides are placed through burr holes on the brain surface and the skull closed with cement, thus restoring the Munro-Kellie principle. Heatless light is conducted into the brain and changes in optical density of this tissue due to vascular pulsation are converted to wave forms by a photoelectric pickup. Trauma and tissue reaction are minimal. Attachment of a similar plethysmograph to the ear by means of Teflon button receptacles allows differential recording of plethysmograms from either vascular bed.

fiber optics; photoelectric technique; Munro-Kellie principle

Submitted on March 5, 1964
Lung volume and ventilatory response to airway obstruction during treadmill exercise
Authors: Tabakin Burton S. , Hanson John S.
Published: December 2017

Measurement of lung volumes and certain ventilatory variables during treadmill exercise with a 5-mm expiratory airway obstruction revealed significant changes in residual volume, expiratory reserve volume, and lung clearance index as compared to values obtained without obstruction. These variations in themselves do not explain previously observed large decrements in oxygen utilization with acute airway obstruction. However, the additive effects of decreased alveolar ventilation and alterations in intrapulmonary gas distribution could account for this phenomenon.

expiratory airway obstruction; lung volume changes with airway obstruction; decreased oxygen utilization with resistance breathing; treadmill exercise and resistance breathing; ventilatory alterations with obstructed expiration

Submitted on April 19, 1963
Criteria for physiological limits for work in heat
Authors: Wyndham C. H. , Strydom N. B. , Morrison J. F. , Williams C. G. , Bredell G. A. G. , Maritz J. S. , Munro A.
Published: December 2017

New physiological criteria are put forward for setting the limits for men at work in hot conditions. They are based upon the fact that the curves relating rectal temperatures to conductances and rectal temperatures to sweat rates have two components. One is where the increases in the sweat rates and conductances, with rise in rectal temperature, are relatively large, i.e., there is a “sensitive” range of control; the second is where the curves of sweat rates and conductances against rectal temperatures reach asymptotes, i.e., become “saturated.” The upper limit of the sensitive range is a rectal temperature of 100.5 F (38.1 C), and the saturated range begins at rectal temperatures of 102.5 F (39.4 C). These concepts explain the “easy,” “difficult,” or “excessive” ranges of conditions of the Fort Knox and Human Sciences Laboratory studies. The great advantage of these criteria over others proposed is that the extent of the physiological strain on the workmen can be assessed, directly and simply, by a measurement of oral or rectal temperatures during the shift, and from these results limits for work can be set for work at specific hot jobs.

assessment of the extent of physiological strain on workmen in heat; determination of physiological limits for work in hot conditions; sensitive and saturated control ranges in man's temperature regulation; relationships between rectal temperature and conductance and rectal temperature and sweat rate

Submitted on March 20, 1964
Effects of immersion of the hand in cold water on digital blood flow
Authors: Hsieh A. C. L. , Nagasaka T. , Carlson L. D.
Published: December 2017

The temperatures of the tip of the middle fingers ( Ts) of nine comfortably warm subjects have been recorded during immersion of all the fingers of one hand in a 27–liter bath containing slowly stirred water at temperatures ranging from 4.6 to 40 C ( Tw). Blood flow ( F = ml/cm2 per min) was estimated from the average Ts for the last 15 min of a 20-min period, Tw and body temperature ( Tb) by using the equation: F = 1,087 x K( Ts – Tw)/ ( Tb – Ts). (K = 0.0134 kcal/cm2 per min per °C.) The increase in F per °C reduction in Tw below 10 C was 0.16 ± 0.077 (P < .05). This value gives a measure of the vasodilatation occasioned by immersion in water below 10 C. The sample regression equation of F on Tw was: F = 4.1 – .16 Tw ± 0.17 (n = 27; range of Tw = 4.6 to 10 C). This method of estimating blood flow at several levels of Tw describes more fully the peripheral circulatory response to cold than methods in which only one level of Tw is used.

cold-induced vasodilatation; temperature and finger blood flow

Submitted on August 28, 1963
Tolerance of men working in hot, humid environments
Authors: Iampietro P. F. , Goldman R. F.
Published: December 2017

Tolerance of acclimatized men working in eight hot, humid environments was studied. Results show that the upper limits for completion of 3 hr of work at a caloric expenditure of 350 kcal/hr are dry bulb (DB) 95 F and wet bulb (WB) 90 F. Rectal temperature is not a good indicator of tolerance under the conditions of our study, while skin temperature and heart rate are. A good relationship is evident between the rapid changes in skin temperature during work (first 10 min of exposure) and tolerance time; thus, these rapid changes may be used to predict tolerance time. Of the physical indexes of thermal stress the best relationship was established between WD (WD = 0.15 DB and 0.85 WB) and tolerance time.

body temperature; tolerance to heat; tolerance to humidity; skin temperature; temperature regulation

Submitted on June 8, 1964
Pulmonary hemodynamics and arterial oxygen saturation in pulmonary embolism
Authors: Caldini Paolo
Published: December 2017

Thoracotomized dogs with a reservoir and mechanical pump substitution of the right heart were subjected to pulmonary embolization by repeated injection of glass microspheres (80-120 뀅) or autologous clots (2-3 mm). Airway pressure was controlled by means of a Starling resistor connected to the expiratory line of the respirator. Following embolization with microspheres, the initial abrupt rise in pulmonary arterial pressure was followed by a more gradual increase, interpreted as due to delayed constriction of pulmonary vascular bed. Following emboli injection, systemic arterial oxygen saturation decreased to 82%, venous admixture rose to 30%. When the end-expiratory pressure was increased from 5 to 20 cm of water, the arterial oxygen saturation rose and venous admixture decreased to values not significantly different from pre-embolic levels. These findings suggest that pulmonary hypertension in pulmonary embolism is due not only to a mechanical obstruction of pulmonary vessels, but that some degree of pulmonary vasoconstriction also occurs when small-sized emboli are used. Arterial hypoxemia associated with pulmonary embolism appears to be due to perfusion of non- or poorly ventilated areas of the lung and not to significant blood flow through arteriovenous anastomoses.

blood tensions; pulmonary edema; pulmonary venoarterial shunts

Submitted on May 4, 1964
Fetal respiratory movements in response to rapid changes of CO2 in carotid artery
Authors: Avery Mary Ellen , Chernick Victor , Young Maureen
Published: December 2017

Recent studies have suggested that chemoreceptors may respond to the rate of change of carbon dioxide as well as its level in arterial blood. The blood which perfuses the carotid body of the fetus would be expected to have less cyclic changes in blood gases since the placenta is the organ of gas exchange. The absence of oscillations in blood gases may contribute to the lack of sustained respiratory activity in utero. Slow changes in fetal blood gases do not initiate fetal respiratory activity. Rapid infusions of blood equilibrated with high CO2 mixtures into the carotid artery of exteriorized fetal guinea pigs and a lamb were associated with gasps. It is proposed that the initiation of rhythmic breathing at birth may depend in part on the oscillations in CO2 which follow use of the lung as the organ of gas exchange.

oscillations, Pco2; first breath; chemoreceptors

Submitted on July 20, 1964
Secondary ventilatory response to exercise: modification by agents which alter CBF
Authors: Krumholz Richard A. , Ross Joseph C.
Published: December 2017

Ventilation increases at the onset of exercise. Another abrupt increase, the secondary ventilatory response, occurs later. This study gives further observations on the secondary ventilatory response and its modification by O2 breathing and other agents which alter cerebral blood flow. The secondary ventilatory response is similar to the response which follows release of arterial tourniquets inflated on the thighs, which is delayed in time of onset by O2 breathing and infusion of aminophylline and NH4Cl and accelerated by CO2 breathing and NaHCO3 infusion. This suggested that the respiratory center response may, to some extent, be dependent upon cerebral blood flow. The onset of the secondary ventilatory response was delayed by 100% O2 breathing. Infusion of NH4Cl significantly delayed the onset of the secondary rise and NaHCO3 tended to make it come sooner. The timing of the secondary ventilatory response, then, was changed by substances which alter cerebral blood flow. It is suggested that the secondary ventilatory response may be due to a blood-borne substance released from working muscles.

regulation of breathing; cerebral blood flow and respiratory center responses

Submitted on January 10, 1964
An experimental chamber for long-term studies of chronic hypoxia in small animals
Authors: Sulkin Norman M. , Jones George
Published: December 2017

An experimental chamber was designed in which chronic hypoxia, as well as adaptation to hypoxia, could be studied over prolonged periods of time in 36 or more small laboratory animals. Rats have been kept in this chamber for periods up to 90 days with oxygen levels from 21% down to 3%, the percentage of oxygen being controllable to 0.25%. The chamber is temperature controlled and maintains a constant relative humidity which may be predetermined. Oxygen levels are maintained by adjusting input of air and nitrogen. The nitrogen tanks are attached to an automatic manifold control which maintains a constant flow of nitrogen even while nitrogen tanks are being changed. It is practical to have a bank of six to eight nitrogen tanks attached to the manifold. Such a bank of nitrogen tanks may last from 4 to 12 days depending on the percentage of oxygen desired. The percentage of oxygen in the chamber is measured directly by means of an oxygen analyzer.

apparatus for producing chronic hypoxia; automatic system for studying hypoxia; temperature and humidity control for small animals

Submitted on June 29, 1964
A comparison of concentric, eccentric, and isometric strength of elbow flexors
Authors: Doss Wayne S. , Karpovich Peter V.
Published: December 2017

A method was developed for a continuous and simultaneous recording of maximum muscle force of the elbow flexors and the degrees of the elbow angles during isotonic contractions. Both concentric and eccentric movements were used. The data thus obtained were compared with the flexors' force measured during isometric contractions at similar angles. It was found that eccentric force was 13.5% greater than isometric force and 39.7% greater than concentric force.

force during movement; isotonic continuous force; electrogoniometer; force, maximum

Submitted on April 6, 1964
Thermoregulation and cold acclimation in a hibernator, Citellus tridecemlincatus
Authors: Pohl Hermann , Hart J. Sanford
Published: December 2017

In the thirteen-lined ground squirrel, Citellus tridecemlineatus, the maintenance of body temperature and oxygen consumption in the cold is improved by acclimation to 18 and 6 C in the laboratory. Heat production at -30 C was greater in animals acclimated to 6 C, whether or not they had been previously hibernating, than in squirrels kept at 28 C. Oxygen consumption was correlated to body weight0.41. This relationship was not significantly affected by changes in ambient temperature. Local heat flow from the dorsal thorax was similar at a given temperature in all acclimation groups but the thermal conductance was greater and the cardiac-subcutaneous temperature difference was smaller in squirrels acclimated to 6 and 18 C. Although shivering was equally high in warm- and cold-acclimated ground squirrels in the cold, nonshivering thermogenesis occurred in curarized cold-acclimated animals exposed to cold or injected with noradrenaline. The results of the study suggest that ground squirrels are regularly exposed to temperatures in their natural habitat which induce considerable cold acclimation.

oxygen consumption—heat production; body temperature—heat conductance; muscular activity

Submitted on July 6, 1964
Acclimatization of older men to work in heat
Authors: Robinson Sid , Belding H. S. , Consolazio F. C. , Horvath S. M. , Turrell E. S.
Published: December 2017

Four men, ages 44—60, repeated daily work experiments in the heat by which they had demonstrated on themselves rapid acclimatization to work in a hot climate 21 years earlier. The work, heat stress, and duration of exposure were those originally found to cause marked hyperpyrexia and circulatory strain in unacclimatized men (mean age 31 years) on the 1st day in the heat. Under these conditions, the subjects sweated at 1.3— 1.5 kg/hr. Tolerance of the men on the 1st day of exposure was no less than when they were younger. Body temperatures and heart rates of the older men were lowered in successive days of exposure and the work was judged progressively easier. Final values of body temperature reached after 5—7 days of exposure were about the same as observed originally after the same number of exposures. Thus, these older men exhibited about the same degree of strain during work in the heat as they did 21 years earlier and acclimatized about as well.

aging; hyperthermia

Submitted on October 1, 1964
Blood serum enzyme activity of dogs exposed to heat stress and muscular exercise
Authors: Bedrak E.
Published: December 2017

The activity of several clinically important enzymes was determined in 11 Alsatian dogs exercised in a temperate environment, exposed to heat stress alone, and exercised in a hot environment before and after heat acclimatization. Enhanced activities of glutamic oxalacetic transaminase (GOT) (P < 0.01), glutamic pyruvic transaminase (GPT) (P < 0.05), lactic dehydrogenase (LDH), phosphohexose isomerase (PHI) (P < 0.05), acid phosphatase (ACP), alkaline phosphatase (ALP), aldolase (ALD), and lipase (LIP) were observed in all dogs exposed to the various physiological stresses. The alteration in enzyme activities of acclimatized dogs was generally smaller than in nonacclimatized animals. Comparison between the two control groups (heat acclimatized versus nonacclimatized) indicates a significant increase in LDH activity (P < 0.01) and lower activities of PHI (P < 0.05), ACP (P < 0.05), and ALP (P < 0.01) in heat-acclimatized dogs.

blood serum enzymes in acute stresses; muscular exercise in a hot environment; nonacclimatized dogs; heat-acclimatized dogs

Submitted on August 17, 1964
Functional blood volume and distribution of specific blood flow in the kidney of man
Authors: Gómez Domingo M. , Demeester Michel , Steinmetz Philip R. , Lowenstein Jerome , Sammons Billy P. , Baldwin David S. , Chasis Herbert
Published: December 2017

A method has been devised to determine the distribution of blood flow through the kidney in man and animals. The studies reported here have been accomplished in humans by using catheterization of renal artery and vein so as to administer a dye indicator at the entrance of the system and measure its behavior at the exit. Through a transformation of the equation of the dye curve the distribution of specific blood flow is inferred. The distribution function seems to be superimposable from one individual to another. The ratio of the half width to the first moment of the distribution function remains nearly constant under widely variable physiological conditions. Renal blood volume and renal capillary surface area are also measured.

specific renal blood flow; functional renal blood volume; renal blood volume; capillary blood volume; renal capillary surface area

Submitted on October 9, 1964
Fetal and maternal temperatures in rabbits
Authors: Hart Frederick M. , Faber J. Job
Published: December 2017

The differences between fetal deep body temperature and maternal aortic temperature were measured in 10 New Zealand white rabbits of 22—29 days gestation with thermocouples thrust into the fetuses immediately after the animals had been killed by a warmed overdose of sodium pentobarbital. Fetal temperatures exceeded maternal temperatures by —2.51 + 0.099.X °C, where X is the gestational age in days. There is 95% confidence that fetal temperatures exceeded maternal temperature by at least 0.25 °C at a fetal age of 29 days. Permanently implanted thermocouples in six nonpregnant rabbits showed that the ventral surface of the abdominal cavity is colder than the aorta, and that the dorsal surface is slightly warmer. Fetal heat loss is partly via the umbilical circulation and partly via the fetal body surface.

tissue temperatures in rabbits; fetal heat loss

Submitted on September 28, 1964
An improved system for prolonged exposure of small animals to artificial low pressures
Authors: Kollias James , Jordan John Patrick
Published: December 2017

A system has been developed for exposing small animals to a low pressure-high oxygen environment. Several unique features such as 1) pressure control, 2) an electronic watering device, and 3) a constant environmental temperature are discussed.

artificial environment; high altitude; high oxygen; watering device

Submitted on July 24, 1964
Change in oxygen tension of shed blood at various temperatures
Authors: Eldridge Frederic , Fretwell L. Kent
Published: December 2017

The change in oxygen tension (pO2) of shed blood was determined polarographically for 2 hr after shedding at temperatures of 37.5, 22—24, and 1 C. The results show that blood pO2 decreases progressively after shedding, that the decrease is especially marked in blood of high initial pO2 values, and that cooling of the sample slows but does not stop the metabolic processes leading to oxygen utilization. The results reaffirm the need for rapid analysis of blood for pO2.

polarographic pO2 analysis; temperature effect; blood metabolism

Submitted on March 6, 1964
Effects of aspirin on detection and tolerance of electric shock
Authors: Dinnerstein Albert J. , Blitz Bernard , Lowenthal Milton
Published: December 2017

Most studies of the effects of aspirin on laboratory-induced pain in humans have shown no effect. A few studies showed analgesic effects. Previous work by the present authors, using indirect measures of pain intensity, showed aspirin to often increase rather than decrease the effects of a noxious stimulus. The present study, employing electric shock and 600 mg of aspirin, examined shock detection and pain thresholds, judgments of discomfort, and the maximum tolerated voltage. Aspirin had little or no effect on most subjects. In a large minority of subjects, aspirin produced a highly reliable increase in sensitivity to shock. These results can be reconciled with the clinical use of aspirin as well as with conflicting laboratory results. Methodological issues are raised concerning this domain of investigation.

pain; analgesia; anxiety

Submitted on December 18, 1964
A strain-gage platform for force measurements
Authors: Petersen W. A. , Brookhart J. M. , Stone Solon A.
Published: December 2017

Design, construction and performance characteristics are described for a rugged, compact, linear force transducer using strain gages as the sensing elements. The device is adaptable to a variety of weighing or force-measurement tasks in the laboratory.

weight measurement; mass measurement; force transducer; weight transducer; load cell

Submitted on November 13, 1964