bluuebunny/crossref_metadata_2025_split huggingface dataset:
Screen filtration pressure method and adhesiveness and aggregation of blood cells
Authors: Swank Roy L. , Roth John G. , Jansen Jerold 
Published: December 2017

An apparatus is described which measures the resistance to flow of blood through a screen with multiple openings 20 μ square. This apparatus is especially sensitive to presence in blood of aggregated blood elements and adhesive materials. It is much less sensitive to changes in hematocrit. The structural features and operation, as well as interpretation of pressure curves are described. viscosity of blood; suspension stability of blood; aggregation of platelets and leucocytes; aggregation of red blood cells; adhesiveness of platelets; adhesiveness of blood elements Submitted on August 5, 1963
Ventilation standards for small mammals
Authors: Kleinman Leonard I. , Radford Edward P. 
Published: December 2017

Ventilation standards for small mammals have been prepared on the basis of the relationship between alveolar ventilation and metabolism. On the assumptions of an average respiratory quotient of 0.85 and physiological dead space directly proportional to tidal volume, the relationship between tidal volume, breathing frequency, and body weight has been derived. The standards are presented in a graphic form and as a slide rule. animal ventilation; artificial respiration; tidal volume, breathing frequency and body weight relationship Submitted on August 15, 1963
Olfactory analogue to directional hearing
Authors: von Békésy Georg 
Published: December 2017

The direction of a sound source can be determined binaurally by using the time difference and the loudness difference of the sound waves arriving at the two ears. Similarly, the direction of an olfactory source can be determined by using the time difference and the difference in sensation magnitude of the olfactory stimuli between the two nostrils as the air surrounding the odorous object is inhaled. Time differences of the order of 0.1 msec can be recognized—a value similar to that found in hearing. Thus the direction of an odor can be determined with a precision of 7–10° in spite of the small distance between the nostrils compared to the distance between the ears. In this respect, there is very little difference between observations made with such odorants as benzol, eucalyptus, cloves, and lavender. The existence of an analogy between hearing and smelling may help to delineate some electrophysiological correlates of the directional sensation, which is so well developed in both senses. localization of olfactory stimuli; interaction between the two nostrils during smelling; time pattern and olfactory localization; olfactory sensation magnitude and duration of stimulus; combination of smell and taste into a single sensation Submitted on November 1, 1963
Muscular exercise at great altitudes
Authors: Pugh L. G. C. E. , Gill M. B. , Lahiri S. , Milledge J. S. , Ward M. P. , West J. B. 
Published: December 2017

Oxygen intake, ventilation and heart rate were measured in six subjects performing ergometer exercise at various altitudes from sea level to 7,440 m (24,400 ft) (Bar. 300 mm Hg) during a Himalayan expedition lasting 8 months. Oxygen intake for a given work rate was constant and independent of altitude, up to the maximum work rate that could be maintained for 5 min. Maximum oxygen intake declined with increase of altitude, reaching 1.46 liters/min at 7,440 m (24,400 ft) in the best subject. Ventilation (STPD) for a given work rate was independent of altitude in light and moderate exercise but increased at each altitude as maximum oxygen intake was approached. Ventilation values of 140–200 liters (BTPS)/min were observed at altitudes above 4,650 m (15,300 ft). Heart rates at altitude were higher at low and moderate work intensities, but the same as or lower than the corresponding sea-level value for the same work load, as maximum oxygen intake was approached. Breathing oxygen at sea-level pressure at 5,800 m (19,000 ft) reduced ventilation and heart rate for a given work rate, restored work capacity almost to sea-level values and increased maximum heart rate. With the aid of data on blood, lung diffusion, and cardiac output from companion studies, the oxygen transport system was analyzed in three subjects, including a high-altitude Sherpa; and evidence is put forward that lung diffusion, cardiac output, and the high oxygen cost of extreme ventilation all contributed to the limitation of exercise at 5,800 m (19,000 ft). respiration, work and altitude; ventilation, work and altitude; heart rate, work and altitude; O2 transport system at high altitudes; altitude acclimatization Submitted on July 29, 1963
Respiratory sinus arrhythmia: a frequency dependent phenomenon
Authors: Angelone Alfonso , Coulter Norman A. 
Published: December 2017

An examination of respiratory sinus arrhythmia is presented. Sinusoidal breathing was varied over a wide frequency range and the amplitude and phase of the accompanying fluctuations of heart rate were observed. These data show that heart rate is not necessarily in phase with respiration as previously described, but rather that the phase angle between heart rate fluctuations and respiration varies with frequency of breathing in a characteristic fashion. The usual descriptions of respiratory sinus arrhythmia are judged to be inadequate since they are shown to represent only a single point on the entire frequency response curve correlating breathing rate with sinus arrhythmia. heart rate fluctuation and respiratory frequency in man; frequency amplitude analysis of respiration-heart rate relationship; heart rate versus breathing: amplitude and phase angle; breathing-induced heart rate changes: phase angle; respiration-induced heart rate changes: phase angle respiratory sinus arrhythmia; respiration versus heart rate: amplitude and phase angle; sinus arrythmia and respiration: amplitude and phase angle Submitted on July 22, 1963
Carbon monoxide in blood: analytical method and sources of error
Authors: Coburn R. F. , Danielson G. K. , Blakemore W. S. , Forster R. E. 
Published: December 2017

A method is described for the analysis of small concentrations of carboxyhemoglobin in blood in which the CO is dissociated from the hemoglobin by oxidizing the latter to methemoglobin with ferricyanide and measured as a gas in an infrared analyzer. The method has a sd of ±0.006 ml/100 ml in the range from 0.1 to 1.0 ml/100 ml. Data are presented which indicate that CO can be formed in a blood sample in vitro if the temperature during oxidation with ferricyanide is higher than about 60 C, if the pH of the reacting solution is 10 or higher, and if metallic mercury is not present during the reaction. It was demonstrated that additional CO is not formed during the analysis with the method described and that the method is highly specific for CO. blood carboxyhemoglobin; carbon monoxide; blood gases; carbon monoxide production; hemoglobin oxidation Submitted on July 19, 1963
A new weighting system for mean surface temperature of the human body
Authors: Ramanathan N. L. 
Published: December 2017

On the basis of an analysis of the skin temperature data on three resting human subjects from 112 experiments, a simple weighting system for computing the mean skin temperature from observations on four areas of the body, namely, chest, arms, thighs, and legs, has been proposed. The proposed system of weighting yields mean skin temperature values identical with the elaborate Hardy-Dubois weighting formula. The value of the medial thigh temperature as an index of the mean skin temperature has also been investigated and discussed. skin temperature measurement Submitted on May 20, 1963
Effect of alterations in end-tidal CO2 tension on flow resistance
Authors: Newhouse Michael T. , Becklake Margaret R. , Macklem Peter T. , McGregor Maurice 
Published: December 2017

The effect of PaCOCO2 on flow resistance and on the mechanical work of ventilating the lung was studied in five normal subjects during sustained voluntary hyperventilation. Hypocapnia caused a consistent increase in flow resistance. Thus, for a minute volume of approximately 30 liters/ min the mean inspiratory flow resistance was 133% greater and the mean respiratory work of ventilating the lungs 68% greater at PaCOCO2 20–25 mm Hg compared to values at 45–50 mm Hg. End-expiratory pressure and compliance were unaffected. Atropine and isoproterenol each markedly diminished the responsiveness of the airways to low PaCOCO2 levels and, given together, blocked the effect completely. These findings could largely account for the increase in oxygen cost of breathing, and in cardiac output associated with voluntary (i.e., hypocapneic) hyperventilation. PaCOCO2; work of breathing; mechanical properties Submitted on June 24, 1963
Measurement of airway resistance with a volume displacement body plethysmograph
Authors: Jaeger M. J. , Otis A. B. 
Published: December 2017

Airway resistance was measured with a volume displacement body plethysmograph in 40 normal subjects breathing at their spontaneous breathing rate. The measurements are based on a method designed by DuBois et al. which was modified in order to extend its applicability. The subjects were rebreathing from a bag containing gas at approximately BTPS conditions. Possible errors in conditioning the gas in the bag were corrected mathematically. The values of airway resistance obtained (1.26 ± .39 cm H2O/liter-1 sec) agree with those published by DuBois et al. and other authors using his technique. The measurements were found to correlate with results obtained on the same subjects with related techniques. The paper also includes measurements of lung tissue viscous resistance and inertance of the gas in the airways. respiratory mechanics; mechanics of breathing; airway inertance; lung tissue viscance Submitted on November 22, 1963
Temperature in the external auditory meatus as an index of central temperature changes
Authors: Cooper K. E. , Cranston W. I. , Snell E. S. 
Published: December 2017

The temperature of the wall of the external auditory meatus has been investigated. Changes in ear temperature reflect changes of sublingual temperature quite accurately and are well correlated with cutaneous vasomotor responses induced by body heating. The temperature of the external auditory meatus is little affected by reflex vasomotor changes. It is easily measured without discomfort or danger and provides a valid indication of temperature changes at the central receptors. There is a considerable temperature gradient down the wall of the meatus so that absolute temperature levels are probably not of value. ear temperature in man; central temperature regulation in man Submitted on February 24, 1964
Effect of cardiac denervation on the maximal capacity for exercise in the racing greyhound
Authors: Donald David E. , Milburn Sidney E. , Shepherd John T. 
Published: December 2017

Ten consecutive time trials were run at 2-day intervals by six racing greyhounds over a 5/16-mile track. Cardiac denervation was then performed on four dogs, and a sham operation that included removal of the pericardium was performed on two dogs. After cardiac denervation, one dog died and another was rejected from the study because of a massive intrathoracic hemorrhage. The time trials were repeated with the addition of telemetry of the heart rate in the four survivors. There was no significant difference between mean preoperative and postoperative race times in the control group. The mean postoperative running speeds of 33.6 and 33.3 mph in the denervated group, although representing a significant slowing of 1.1 and of 2.1 mph, respectively, from preoperative values, indicate the adequate manner in which the denervated heart meets the circulatory demands of maximal running effort. cardiac output; heart rate and exercise Submitted on March 11, 1964
Limitations to prediction of maximal oxygen intake
Authors: Rowell Loring B. , Taylor Henry L. , Wang Yang 
Published: December 2017

The predictability of maximal O2 intake (max Vo2) was studied in four groups of normal men, 18–24 years of age. Prediction of max Vo2 was made from pulse rate and Vo2 at a single submaximal workload at an ambient temperature of 78 F by use of the nomogram of Åstrand and Ryhming (1954) and underestimated actual max Vo2 by 27 ± 7% and 14 ± 7% in a sedentary group, before and after 2frac12–3 months of physical training, and by 5.6 ȁ 4% in a group of ten endurance athletes. Accuracy of prediction in all groups varied with approximation of pulse rate to 128 beats/min at 50% of max Vo2. Nonspecific stresses increased predictive errors in all groups. Constants b (slope) and A (intercept) in the regression equation Vo2 = bP – A (where P is pulse rate), were determined from Vo2 and pulse measured at four submaximal workloads requiring 13–28 ml O2/kg min. Prediction of max Vo2 by extrapolation of the slope to maximal pulse rate resulted in underestimation of 700–800 ml O2/min. Removal of 14% of circulating hemoglobin decreased max Vo2 by 4% but there was no change in pulse rates or predicted max Vo2. The relationship of RQ to V22 during work provided no reliable basis for prediction of max Vo2. exercise pulse rate, oxygen intake, relationship; pulse rate, oxygen intake relationship in exercise; metabolic rate, maximal aerobic prediction of; aerobic metabolic rate, maximal, prediction of; phlebotomy, effect on maximal oxygen intake, pulse rate; blood loss, effect on maximal oxygen intake, pulse rate; training, effect on maximal oxygen intake, pulse rates; physical conditioning, effect on maximal oxygen intake, pulse rates Submitted on October 4, 1963
Basal metabolism and respiration in men living at 5,800 m (19,000 ft)
Authors: Gill M. B. , Pugh L. G. C. E. 
Published: December 2017

Respiratory determinations were carried out on eight members of the Himalayan Scientific and Mountaineering Expedition 1960—1961 and three Sherpas during a prolonged stay at 5,800 m (19,000 ft). Ventilation and oxygen uptake were similar in both groups, although the Sherpas were smaller men. The Sherpas had lower alveolar ventilation, higher PaCOCO2 and lower PaOO2 values than the scientists. Among six of the scientists mean basal metabolic rate was 10% above the mean value predicted from sea-level standards. There was no increase in the two others, who did not acclimatize. The mean basal metabolic rate in the three Sherpas was +21%. The findings were not explained by the extra O2 cost of increased breathing, changes in body composition, or exposure to cold, although this may have been a factor in the Sherpas. The results were similar to recent South American data on residents at 4,540 m (14,900 ft). It was concluded that acclimatization to great altitudes in man is associated with increase in basal metabolism, but there is insufficient evidence as to whether this is a response to hypoxia or other environmental factors. basal respiration; acclimatized men; high altitude (5,800 m) Submitted on March 30, 1964
Influence of gravitational forces on function of lower extremity muscles
Authors: Houtz S. J. 
Published: December 2017

Action potentials were recorded by surface electrodes from the quadriceps, hamstrings, tibialis anterior, and triceps surae muscle groups as 12 normal adolescents performed a series of changes in posture. Postural movements consisted of sitting, standing, squatting, sit-ups, unilateral standing with contralateral lower extremity exercise, trunk forward bending with knee flexion and extension, and the head stand. Photographs were taken to assist in analyzing change in body position during the activities. The hamstrings and triceps surae resist forces tending to flex the supporting extremity when the trunk or contralateral limb is suspended anteriorly. The quadriceps and tibialis anterior act volitionally or by lengthening contraction to move the body vertically. The muscles participating in an activity and their specific functions are influenced by gravitational forces, the weight and position of various body segments, and the point of contact with the supporting surface. electromyography; thigh and leg muscles; postural exercises; human male and female Submitted on February 3, 1964
Modification of thermoregulatory responses to cold by hypnosis
Authors: Kissen Abbott T. , Reifler Clifford B. , Thaler Victor H. 
Published: December 2017

The effects of hypnosis on thermoregulatory responses were studied in nonacclimatized acutely cold-exposed men. Forty exposures (4.5 @#X2013;5.0 C) were conducted in an environmental chamber under both hypnosis and nonhypnosis conditions. Five subjects, wearing 1 clo insulation, were cold exposed for 1 hr, four times for each condition, and each subject served as his own control. Variables monitored included mean skin and rectal temperatures, heart and shivering rates, basal skin resistance, and vigilance task performance. In hypnosis, shivering was suppressed, heart rate lowered, and vigilance task performance improved. Basal skin resistance differed in terms of pattern and level, being generally higher under hypnotic conditions. Rectal temperatures were lower despite maintaining skin temperature at the same level as during nonhypnosis conditions. These findings indicate that with the thermal stress imposed and levels of trance achieved, there is a general amelioration of the psychophysiological effects of the stress. The mechanism responsible for this form of “adaptation” remains speculative but is consistent with generalized suppression of sympathetic activity. thermoregulation; cold exposure; adaptation; sympathetic nerve activity; shivering; basal skin resistance; vigilance task performance Submitted on March 12, 1964
Reactions to heat of aborigines and Caucasians
Authors: Wyndham C. H. , McPherson R. K. , Munro A. 
Published: December 2017

A study was made of the physiological reactions to heat of samples of Australian aborigines and Australian Caucasians in the hot, humid tropics. Their results were then compared with those of unacclimatized and acclimatized Caucasians (South Africa). The Australian shows signs of a partial degree of acclimatization in that his heart rate and rectal temperature are lower and his sweat rate is higher than those of the unacclimatized South African Caucasian. The aborigine presents a less clear picture in that his rectal temperature is lower but his heart rate and sweat rate is the same as the unacclimatized Caucasian. A striking difference between the Caucasians and aborigines in Australia is the much higher sweat rates of the Caucasians. The lower sweat rates of the aborigine might result from the morphological feature of a greater surface area: mass ratio whereby he loses heat by radiation and convection more adequately than the Caucasian and therefore is able to conserve sweat; alternatively, he appears to have a more sensitively adjusted thermoregulatory control channel between rectal temperature and sweat rate. acclimatization to heat in northern Australia; adaptation to heat of aborigines; Caucasians and aborigines in Australian tropics; heat reactions in the tropics; morphology and adaptation to heat Submitted on February 28, 1964
Effect of alveolar hypoxia on pulmonary vascular resistance
Authors: Lloyd Thomas C. 
Published: December 2017

The responses to graded hypoxia in 58 excised dog lung lobe preparations have been measured during constant perfusion and ventilation. When perfused with blood, alveolar hypoxia always evoked a pressor response, whereas a dilator response always appeared when a synthetic perfusate was used. Hexamethonium, atropine, and brom-lysergic acid diethylamide did not alter the pressor response; Dibenzyline appeared to diminish the response but this may have been due to the reversal of effect of any epinephrine present. A pressor response could also be produced with KCN. The response to alveolar hypoxia was shown to be unrelated to pulmonary arterial blood Po2, but the resistance increase was demonstrated to be in the precapillary vessels. The hypoxic pressor response was transient and easily depressed by a period of severe hypoxia even though pressor drug responses remained unchanged. The possibility of mediation of the arterial narrowing by a reflexlike mechanism is considered. Note: (With the Technical Assistance of Emily McCartney) direct vascular effects of hypoxia; reflex vasoconstriction tissue hypoxia Submitted on March 27, 1964
Aerobic and anaerobic work capacity after dehydration
Authors: Saltin Bengt 
Published: December 2017

Ten subjects performed standard exercise tests at two submaximal loads and one maximal load before and 90 min after dehydration caused predominantly by 1) a thermal, 2) a metabolic, and 3) a combined thermal and metabolic heat load applied for 2.5@#X2013;4 hr. Each subject interrupted dehydration so that almost the same decrease in body weight was attained in the three situations (1.7@#X2013;4.6 kg). Oxygen uptake, heart rate, and concentration of blood lactate were measured during the exercise. At the submaximal loads there was no change in oxygen uptake after dehydration but the heart rates were significantly higher (mean difference 13 beats/min) and blood lactates were lower (from 0.5 after (1) to 1.6 (2) mmoles/liter). At the maximal load there were no significant changes in oxygen uptake and heart rate but work times decreased markedly (6@#X2013;4 min) as did blood lactates (14.0@#X2013;10.4 mmoles/liter) especially after exercise dehydration. physical work capacity Submitted on January 20, 1964
Circulatory response to submaximal and maximal exercise after thermal dehydration
Authors: Saltin Bengt 
Published: December 2017

Data on cardiac output and stroke volume are given for four subjects at various levels of muscular work up to the individual's maximum. No significant difference was found between the dye-dilution and the acetylene methods. Three subjects were studied under normal conditions and after dehydration (exposure to heat with a reduction in body weight of up to 5.2%); circulatory data were measured at rest and during exercise at two submaximal and one maximal work load. The decrease in body weight was accompanied by a reduction in plasma volume of up to 25%. After dehydration, the major change in the hemodynamic response to work in a sitting position at the submaximal loads was a decrease in stroke volume and an associated increase in heart rate, so that the cardiac output remained almost unaltered. Both these changes were significantly correlated to the reduction in body weight and plasma volume. When after dehydration the submaximal work load was performed in a supine position, no increase in heart rate was noticed compared with that before dehydration. Dehydration produced no significant change in oxygen uptake, cardiac output, or stroke volume during maximal exercise in a sitting position. However, the maximal work time was much shorter and there was a marked decrease in maximal blood lactate. comparison dye-dilution-acetylene methods; plasma volume; lactic acid Submitted on August 12, 1963
Load and local muscular isometric endurance with occluded blood supply
Authors: Start K. B. 
Published: December 2017

The isometric endurance of the palmar flexors was measured in 11 subjects who had the blood supply to the forearm occluded by means of a pressure cuff on the upper arm. The endurance load was determined as a percentage of the maximum strength of each muscle group and, in this study, varied from 35 to 85%. Load was graphed against endurance and equations were established for the relation which, under the conditions of high loading in the experiment, appeared to be linear. contraction metabolism; strength as a predictor of endurance; contraction producing intramuscular vascular occlusion Submitted on December 30, 1963