bluuebunny/crossref_metadata_2025 huggingface dataset:
Breathing in brief exercise
Authors: Craig F. N. , Cummings E. G.
Published: December 2017

Two men ran for 20 or 60 seconds while inhaling air, oxygen or 4% carbon dioxide. Inspired respiratory minute volume was determined for each breath. Ventilation increased suddenly in the first breath with minimal changes in end-expiratory carbon dioxide tension and respiratory exchange ratio to a rate that remained constant for 20 seconds before increasing further. The rate of carbon dioxide output was uniform during the first 20 seconds. A 12% grade did not increase ventilation or oxygen uptake during runs of 20 seconds, but in the first minute of recovery, ventilation was 64% greater than after level runs. Inhalation of oxygen inhibited ventilation by 24% in the 20-second periods before and after the end of a 60-second run. Inhalation of carbon dioxide begun at rest produced increments in ventilation and end-expiratory carbon dioxide tension that varied little during running and recovery. In the 20-second runs ventilation varied with speed but appeared independent of ultimate metabolic cost.

Submitted on January 21, 1960
Electrodiagnosis of vitamin E-deficient and denervated skeletal muscle of rabbits
Authors: Fudema John J. , Oester Yvo T. , Fizzell James A. , Gatz Arthur J.
Published: December 2017

Nutritional muscular dystrophy was produced in rabbits maintained on a vitamin E-deficient diet. Electrodiagnostic data collected from the anterior tibial muscles of these animals were compared with data from control animals on the same diet supplemented with vitamin E, and animals on the control diet which had unilateral surgical denervation of one anterior tibial muscle. Strength-duration curves of muscles developing dystrophy demonstrated a pronounced upward trend and were complex, containing two segments with a discontinuity at their juncture. This upward trend and the discontinuity of the strength-duration curves suggest the presence of denervation, for these are characteristically found in muscle denervated by partial or complete section of the motor nerve. Chronaxie, repetitive stimulation and galvanic tetanus ratio values of dystrophic muscle in the late stages were found to be comparable to the observations of the same criteria in the early stages of denervated muscle. No change in threshold of vitamin E-deficient muscle to faradic stimulation was found. In denervated muscle, response to faradic stimulation persisted, though with increased threshold at the end of a 60-day observation period.

Submitted on December 9, 1959
Graphic visualization of the relations of metabolic fuels:heat:O2:CO2:H2O:urine N
Authors: MacHattie Lorne A.
Published: December 2017

The quantitative relations among the various measured and calculated variables of metabolism can be described much more clearly by graphs than in words or tables. A system of graphing is presented whereby these relations can be shown on any of 105 different graphs in terms of straight lines. The metabolic variables treated are: carbohydrate, fat, protein (or urinary nitrogen), heat, O2, CO2 and metabolic water. Since the values of any three of these are sufficient to define the metabolic situation, they define on the graph a point which stands for that situation, and from which the relative values of all the other variables can be read off. Theoretical principles of the system are given whereby the general layout of any of the 105 graphs can be easily found. The graph on axes of O2 /heat vs. CO2/heat is selected for development and is used to show the relations of the metabolic variables, not only for the case of simple catabolism of fuel mixtures, but also for cases involving fuel syntheses, ketosis, lactic acid production, and measurement errors due to unsteady states.

Submitted on July 8, 1959
Heat output in the cold from hands of Arctic fishermen
Authors: Hellström B. , Andersen K. Lange
Published: December 2017

The heat output from the hands of Arctic fishermen was studied by water calorimetry, using an initial water-bath temperature of 4°C. The fishermen were compared with a group of young men not habituated to work in the cold. The subjects were investigated when comfortably warm and when kept in heat debt by being chilled. The total heat output from the hand during the 30 minutes of calorimetry ranged from 1907 cal/100 ml hand tissue/min. (cold room) to 4886 cal/100 ml hand tissue (warm room). There was found no significant difference of the mean heat output between the two groups, neither when they were in general heat balance, nor when in heat debt. One subject who developed cold urticaria showed a considerably higher heat output than any of the other persons investigated. The results do not agree with the view that men habituated to working in the cold with their hands show an increased blood flow in the cold when studied under environmental temperatures low enough to produce a general vasoconstriction.

Submitted on March 21, 1960
Effects of ventilatory pattern and body position on lung volume in dogs
Authors: Kilburn Kaye H. , McDonald Jerry , Piccinni Frank P.
Published: December 2017

The functional residual capacity (FRC) of paralyzed pump-ventilated dogs was measured by open-circuit helium dilution at various rates and volumes of ventilation and the FRC's of spontaneously ventilated dogs were compared after changes in body position. When tidal volume was constant, increases in rate and minute volume increased FRC. The FRC tended to increase with larger tidal volumes when minute ventilation was constant. An inclination of 30 degrees increased FRC 23.8% (mean for 41 dogs) above the FRC measured in the horizontal position, whereas a declination of 30 degrees decreased FRC by 65.8% (mean for 8 dogs). It is suggested that larger tidal or minute volumes open pulmonary units which are closed by surface tension forces when the volume or duration of inflation is less. Tilting head-up or head-down changes the position of the diaphragm and the abdominal contents in the thoracic ‘cylinder’ to accommodate more or less gas volume in the thorax.

Submitted on February 29, 1960
Static pressure-volume characteristics of lungs in normal males
Authors: Permutt Solbert , Martin H. B.
Published: December 2017

The static pressure-volume characteristics of the lungs were determined in 28 normal males between the ages of 21 and 76 years. Transpulmonary pressures were measured in relation to absolute lung volumes throughout the entire range of the vital capacity, both on inspiration and expiration. There was an increase in residual volume and a decrease in vital capacity, but no change in the slope or position of the pressure-volume curve with advancing age. It appeared that the older subjects were unable to change transpulmonary pressure between residual volume and total lung capacity to the same extent as the younger subjects. The results suggest that with advancing age there is little change in the intrinsic static pressure-volume characteristics of the lungs themselves, and that all of the significant changes with age are more likely due to changes in either the compliance or muscle power of the thorax.

Submitted on December 24, 1959
Rate of flow of parotid secretion during constant stimulation
Authors: Weber Thomas B.
Published: December 2017

Thirty-one healthy, male individuals in a 17–21-year-age group were subjected to a bilateral collection of parotid secretion. Flow was elicited by chewing flavored chicle for a total stimulation period of 1 hour. All collections were made under carefully controlled regimen with minimal environmental and physical changes tolerated. Minute-to-minute rates of flow were not found to be predictable, but there was a pattern which was dependent upon the masticatory and gustatory stimuli. In a given individual it was possible to predict the flow rate of each of the parotid glands over 15-minute intervals. No glandular exhaustion was evident and hourly rate of flow was remarkably constant. Each gland showed an inherent individuality which was apparent throughout the complete period of excitation.

Submitted on March 14, 1960
Factors affecting survival of mouse bone marrow cells during freezing and thawing in glycerol
Authors: Tran Phan The , Bender M. A.
Published: December 2017

The effects of freezing rate, thawing rate and repeated freezing and thawing on the survival of mouse bone marrow cells frozen in various concentrations of glycerol were studied. The ability of thawed cells to promote recovery in lethally irradiated (900 r) mice was used as a measure of their viability. The experiments show that for best survival the cells should be ‘slow’ frozen in an additive solution, such as 15% glycerol. They should be ‘fast’ thawed. Repeated freezings and thawings lead to both a loss of cells and a more rapid loss of their ability to promote recovery. It is unnecessary to remove the glycerol from cells if they are to be used soon after thawing.

Submitted on February 8, 1960
An improved procedure for determination of cardiac output by a conductivity method
Authors: Hershgold Edward J. , Steiner Sheldon H. , Sapirstein Leo A.
Published: December 2017

The applicability of the hematocrit dilution technique employing arterial blood conductivity changes to the determination of the cardiac output has been extended by a) electronic damping of the detecting circuits, which permits greater amplification of the signal without increasing the variability of the base line that occurs during each cardiac cycle, and by b) development of a solution isoosmolar and isoconductive with plasma that substitutes for autogenous plasma in the procedure. The preparation of the synthetic solution is described. It is shown that this solution gives results indistinguishable from those obtained with plasma. Values are given for the conductivity and osmolarity of dog plasma.

Submitted on December 3, 1959
Mechanical properties and dimensions of the major pulmonary arteries
Authors: Patel Dali J. , Schilder Donald P. , Mallos Alexander J.
Published: December 2017

Page 94: Dali J. Patel, Donald B. Schilder and Alexander J. Mallos, “Mechanical properties and dimensions of the major pulmonary arteries.” Column 1, paragraph 5, line 1 should read: The mean value for ∆R/∆P × 10+3 in control animals. Column 2, table 1, line 9 should read: ∆R/∆P × 10+3.
Generation of coagulation product I and its interaction with platelets and phospholipids
Authors: Horowitz Herbert I. , Spaet Theodore H.
Published: December 2017

Product I, a potent intermediate of blood thromboplastin formation, was generated by incubating diluted adsorbed plasma and serum reagents with calcium and was assayed with a substrate plasma containing added crude cephalin. Product I generation is accelerated by small quantities of thrombin. The subsequent reactions of fully formed product I leading to the formation of active blood thromboplastin have been found to be virtually instantaneous in the presence of optimal concentrations of available phospholipids. A time-consuming reaction of approximately 15 seconds occurs between the product I and intact platelets, wherein the platelet phospholipid is made available for blood thromboplastin generation.

Submitted on August 11, 1960
Altitude tolerance of chickens and pigeons
Authors: Altland Paul D.
Published: December 2017

Chickens and pigeons were exposed for 6 hours to various simulated high altitudes to determine the highest altitude tolerated without deaths and the lowest altitude at which there are no survivors. Six- to seven-week-old chicks were less tolerant than twenty-to twenty-five-week-old chickens. All chicks survived exposure to 12,000 feet, 90% survived 14- and 16,000 feet and, at higher altitudes, the survival was progressively lower until none survived at 26,000 feet. All older chickens survived exposure to 16,000 feet; approximately 88% survived altitudes up to 20,000 feet and, above this, survival was greatly decreased until none survived at 26,000 feet. Roosters showed a greater altitude tolerance than hens, a sex difference contrary to that found in mammals. Six- to ten-week-old pigeons survived 6-hour exposures to all altitudes including 28,000 feet and 97% survived exposure to 30,000 feet. Only 27% survived 32,000 feet and all died within 10 minutes at 34,000 feet. The results indicate that chickens have a much lower altitude tolerance than all other small warm-blooded animals previously studied.

Submitted on July 11, 1960
Age trends in fat in normal and obese children
Authors: Pařízková Jana
Published: December 2017

Body density was determined in 151 normal boys and girls 9–17 years old by hydrostatic weighing and simultaneous determination of residual lung volume by the nitrogen dilution method. Also, 56 obese children 9–15 years old were studied. Body composition changed characteristically in the groups of normal children. In boys, density at 9 years was 1.062 (S.E. = 0.003) and fell to 1.048 (S.E. = 0.004) at 11–13 years; it rose to 1.073 (S.E. = 0.002) at 16, indicating a relative decrease in fat content and increased development of lean body mass. In girls, values were more stable-1.041–1.042 (S.E. = 0.003–0.004) on the average, except in the year 13–14 when body density increased to 1.051 (S.E. = 0.004). After the start of clinical puberty, body density again fell to 1.038 (S.E. = 0.003) indicating increased fat content. There was significant sexual difference in body density before the beginning of prepuberal acceleration of growth and later with the start of clinical puberty. Body density for obese boys 9–12 years old was 1.010 (S.E. = 0.002) and for obese girls of the same age 1.009 (S.E. = 0.002). In 13–15-year-old obese boys, density was 1.016 (S.E. = 0.003) and for girls was 1.012 (S.E. = 0.0039); i.e. in obese children no sex or age differences in body density were found.

Submitted on May 9, 1960
Hormonal determinants of mammalian tolerance to acceleration stress
Authors: Polis B. David
Published: December 2017

The pituitary-adrenal hormonal axis has been implicated as a critical factor in the survival of the rat to acceleration stress. The physiological end point for the tolerance of animals to high positive acceleration stress was obtained by determining the time to reduce the heart rate from 8 to 2 beats/sec. at 20 g. With this technique, a significant increase (300%) in the survival time of rats to 20 g was found following hypophysectomy. A significant loss (60%) of tolerance to high acceleration stress was found in adrenalectomized rats. The procedures of hypophysectomy plus adrenalectomy apparently opposed the effect of each operation alone in the rat to yield an animal that tends to approach the normal rat in its ability to tolerate acceleration. A significant drop in the tolerance to acceleration of hypophysectomized rats was found 7 and 15 weeks after operation compared to that found with the animals 3 weeks after hypophysectomy and a significant increase in the tolerance of the adrenalectomized rat was found 11 weeks after operation compared to the tolerance at 5 weeks after adrenalectomy. In both operated populations, the direction of change was toward the tolerance level of the normal rat.

Note:

(With the Technical Assistance of Anne Zella)

Submitted on September 12, 1960
Effect of diet on body temperature during sleep in the cold
Authors: Kreider Marlin B.
Published: December 2017

Thirteen young soldiers were divided into two groups and fed liquid diets of similar caloric content but of different composition. One group was fed a normal, high-fat, high-carbohydrate and normal diet in the first, second, third and fourth weeks, respectively; the second group was fed a normal, high-carbohydrate, high-fat and normal diet during the same periods. Three meals were eaten at 8 a.m., 5 p.m., and 10:15 p.m., at which times 30, 30 and 40% of the daily calories were consumed. Measurements of skin (11 points) and rectal temperatures were made at one-half-hour intervals throughout the night when the subjects were in sleeping bags at an ambient temperature of –30°F. Protection against the cold was designed to be inadequate to maintain thermal comfort. Composition of the diet had no effect on rectal, mean weighted skin or toe temperatures throughout the night with a few exceptions. No physiological significance is ascribed to these exceptions since the differences were very small. It is concluded by comparison with a previous study that caloric content rather than composition of the diet is the important factor in decreasing rates of body cooling of men sleeping in the cold.

Submitted on October 14, 1960
Effect of acetazolamide on metabolic rate of man
Authors: Coppen A. J. , Mezey A. G.
Published: December 2017

Acetazolamide administered intravenously to normal subjects failed to alter the metabolic rate in man although animal experiments had indicated that the drug administered in comparable doses over a period of weeks produced a marked diminution in oxygen consumption.

Submitted on June 23, 1960
Effects of carbon dioxide on cold-exposed human subjects
Authors: Bullard Robert W. , Crise John R.
Published: December 2017

Human subjects were exposed to an ambient temperature of 5 C for 75-min periods. Subjects breathed 2.5%—6% carbon dioxide for selected time periods during the exposure. Carbon dioxide appeared to inhibit shivering. After carbon dioxide inhalation, shivering and metabolism were greatly increased. When 6% carbon dioxide was inhaled for 30 min, the inhibition was overcome and shivering and metabolism approached high levels. The increased respiratory heat loss associated with carbon dioxide breathing may be one factor causing the breakthrough of the inhibition.

Submitted on November 14, 1960
Cutaneous vasodilatation elicited by body heating in calf, forearm, cheek, and ear
Authors: Senay Leo C. , Christensen Margaret , Hertzman Alrick B.
Published: December 2017

When seminude subjects were exposed to a slowly rising ambient temperature (25—45 C), the onset of cutaneous vasodilatation occurred simultaneously in the calf, forearm, cheek, and ear, and the further progress of the vasodilatation was similar in the last three regions. That in the calf and toe often differed from that in the forearm. Either the vasodilatation in the calf was small or it stabilized early while the forearm vessels continued to dilate markedly. One subject repeatedly presented an exception in that a marked vasodilatation in the calf considerably exceeded that in the forearm. He was a poor sweater and exhibited unusually high skin temperatures. The usual failure of the skin temperature to rise as much in the calf as in the forearm appeared to be closely related to the lesser cutaneous vasodilatation. There was no evidence that local sweating elicited local vasodilatation; on the contrary, evaporative cooling seemed to decrease the vasodilatation, particularly in the calf. The cutaneous vascular events were followed continuously in each region by means of photoelectric plethysmography.

Submitted on December 27, 1960
Effect of muscle strength and endurance development on blood flow
Authors: Vanderhoof Ellen R. , Imig Charles J. , Hines H. M.
Published: December 2017

Studies were carried out to investigate the effect of hand grip strength and/or endurance improvement on blood flow through the muscles involved. One group of subjects trained for strength development and another for endurance development throughout a 29-week period. At regular intervals blood flow was measured under resting conditions and also following three different test exercise stresses designed to test the functional capacity of the vascular bed. Subjects who participated in the strength training program made significant gains in strength but not in endurance, while those subjects who trained for endurance improved in both strength and endurance. Resting blood flow was not changed significantly as a result of either training program. Significant changes in the blood flow response to the test exercise stresses were noted; these changes were associated with endurance rather than strength improvement.

Submitted on April 3, 1961
Regional blood flow and vascular resistance in response to oxytocin in the pregnant sheep and dog
Authors: Assali N. S. , Holm L. , Parker H.
Published: December 2017

The effects of oxytocin on regional blood flow and regional vascular resistance were investigated in a group of pregnant ewes and bitches not in labor and in another group in early labor. Single injections or intravenous drip infusion did not change significantly arterial pressure, cardiac output, electrocardiogram, and renal, iliac, femoral, and carotid blood flows in any of the animals studied. The effects on the pregnant uterus were negligible before the onset of spontaneous labor. Only when the animal was in labor did oxytocin produce an increase in uterine contractions accompanied by a significant decrease in uterine blood flow. The data indicate that in the pregnant sheep and dog the circulatory action of oxytocin is limited to the pregnant uterus in labor and that the decrease in blood flow is probably due to an increase in intramural vascular resistance caused by the contracting myometrium around the uterine arterioles.

Submitted on May 5, 1961
Leucocyte count variation in young chicks during an 18-hour period
Authors: Glick Bruce
Published: December 2017

Page 965: Bruce Glick, “Leucocyte count variation in young chicks during an 18-hour period.”

Table 1, section B, should read: B.∗ Recorded at 7 different time intervals.
Anthropometric comparison of muscular and obese men
Authors: Taylor W. Leonard , Behnke Albert R.
Published: December 2017

Body weight is frequently too gross as a reference base for physiologic parameters. Adequate techniques are available to measure such components as water and fat, but these procedures are time consuming and require special apparatus. The high correlation, however, between anthropometric circumferences, stature, and body weight makes possible a partition of weight into components, W( A) and W( B). In obese men it can be shown that the “trunk” W( A) component greatly exceeds the weight of W( B) referable chiefly to the extremities. In athletes, W( B) exceeds W( A). The average of W( A) and W( B) closely approximates body weight. From the anthropometric perimeters it is possible to calculate d values which can be used to construct a somatogram to provide quantitative representation of bodily configuration. The technique for procurement of the anthropometric data can be carried out on large numbers of individuals in minimal time and requires only a tape measure.

Submitted on April 28, 1961
Metabolic cost of head-stand posture
Authors: Rao Shanker
Published: December 2017

Metabolic cost to the human body of various postures has been assessed by many workers. The cost with the body in the topsy-turvy posture, or while “standing on the head,” has not been reported so far. Energy expenditure was calculated indirectly by estimating the amount of oxygen consumed while in a particular posture. A Benedict-type recording spirometer was used for this purpose. The subjects were six healthy medical students. The mean cost of standing on the head was determined to be 336 ml, or 1.62 kcal/min, and that of “suspension by the feet” to be 300 ml, or 1.44 kcal/min. The possible causes of increased consumption in relation to the “standing erect” posture are discussed.

Submitted on May 26, 1961
Reproducibility of a glucose tolerance test
Authors: Acland J. D. , Clayton H. , Mitchell B.
Published: December 2017

A statistical method is described for testing the significance of changes in the glucose tolerance of experimental subjects in different conditions. Statistically significant changes in glucose tolerance from day to day were observed in seven normal men who underwent glucose tolerance tests on 3 successive days. No statistically significant changes in glucose tolerance were found on the 2nd day after a glucose tolerance test in further experiments using five normal men. Possible physiological mechanisms by which the performance of a glucose test could cause alterations in glucose tolerance are discussed.

Submitted on December 19, 1960
An electrical analyzer for carbon dioxide in respiratory gases
Authors: Bernstein Leon , Yoshimoto Chiyoshi
Published: December 2017

The analyzer described was de signed for measuring the concentration of carbon dioxide in the bag of gas from which the subject rebreathes in the “rebreathing method” for estimating the tension of carbon dioxide in mixed venous blood. Its merits are that it is cheap, robust, simple to construct and to service, easy to operate, and accurate when used by untrained operators. (Medical students, unacquainted with the instrument, and working with written instructions only, obtained at their first attempt results accurate to within ±0.36% [sd] of carbon dioxide.) The instrument is suitable for use by nurse or physician at the bedside, and also for classes in experimental physiology. Some discussion is presented of the theoretical principles underlying the design of analyzers employing thermal conductivity cells.

Submitted on July 13, 1961
Hemodynamic responses to oxygen breathing in man
Authors: Eggers G. W. N. , Paley H. W. , Leonard J. J. , Warren J. V.
Published: December 2017

Hemodynamic responses to breathing 100% oxygen for an average of 30 min were studied in eight healthy male volunteers. Cardiac output and related determinations were performed with central injections of a radioactive indicator and calculated by the method of Stewart and Hamilton. Arterial blood gas analyses were performed in each phase of the study. Slight but statistically significant decreases in cardiac index and heart rate were observed during oxygen breathing. There was no change in the central blood volume, but a masked increase in pulmonary blood volume may have occurred. Statistically significant increases in peripheral vascular resistance, mean arterial pressure, and both systolic and diastolic arterial pressures occurred during oxygen breathing and persisted at least 40 min after oxygen was discontinued.

Submitted on May 1, 1961
Estimation of effective renal plasma flow using I131-labeled Hippuran
Authors: Schlegel J. U. , Smith B. G. , O'Dell R. M.
Published: December 2017

Values of PAH and Radio-Hippuran clearances, obtained simultaneously in 96 individual renal clearances for 16 patients, were plotted against each other and a regression line calculated which shows a linear relationship between the two substances. Knowing the value of the Radio-Hippuran clearance, by use of the regression line, the effective renal plasma flow in terms of PAH clearance can be estimated. This method of determination gives an accurate and less laborious measure of renal plasma flow than chemical determinations of PAH.

Submitted on July 21, 1961
Myoglobin content and enzymatic activity of muscle and altitude adaptation
Authors: Reynafarje Baltazar
Published: December 2017

Quantitative determinations of myoglobin were made in the sartorius muscle of healthy human subjects native to sea level and high altitude. The specific activities of the reduced form of diphosphopyridine nucleotide oxidase (DPNH-oxidase), DPNH- and the reduced form of triphosphopyridine nucleotide (TPNH)-cytochrome c reductases, transhydrogenase, and isocitric and lactic dehydrogenases were also examined. There was found a significantly higher myoglobin concentration in the muscle of the high-altitude native as compared with the sea-level resident. The enzyme systems DPNH-oxidase, TPNH-cytochrome c reductase, and transhydrogenase similarly showed a significantly higher activity in the altitude resident. It was concluded that the respiratory capacity of the muscle was apparently higher in the altitude native than in the sea-level one. The enhanced enzymatic activity was probably related to the higher pigment content of the skeletal muscle. Results on myoglobin determinations in several other muscles from certain sea-level patients are discussed.

Submitted on July 24, 1961
Thermal influence of sunshine and clothing on men walking in humid heat
Authors: Craig F. N. , Cummings E. G.
Published: December 2017

For two men walking on a treadmill and wearing two layers of permeable clothing, the same physiological strain measured by the rate of increase in mean body temperature could be produced a) next to a building outdoors in the sunshine with an average air temperature of 85 F and humidity of 20 mm Hg and b) indoors with the same humidity and an air temperature 10 F higher. Under these conditions, the underwear was mainly wet with sweat and the outer layer was mainly dry. In comparable indoor tests on a third subject, the temperature of the underwear approached equilibrium 1 or 2 F lower than the temperature of the skin at air temperatures of 85 and 115 F. The error in calculating clothing insulation introduced by assuming the clothing to be dry is determined by the size and direction of the temperature gradient between skin and air. Adding 10 F to the indoor air temperature does not duplicate all the effects of sunshine.

Submitted on September 15, 1961
Postexercise hyperemia in trained and untrained subjects
Authors: Elsner Robert W. , Carlson Loren D.
Published: December 2017

Physiological responses of athletes and nonathletes to treadmill exercise at 4 mph on a 10% grade for 5 min were compared. Some nonathletes were studied again after 4 weeks' physical training. Whereas the increase in oxygen consumption during exercise and the oxygen debt were similar in all groups, heart rate and blood flow in the leg increased less and returned to resting values more rapidly in athletes and in trained nonathletes than in untrained nonathletes. The time required for the return of blood flow to pre-exercise levels was greater than that necessary for the repayment of O2 debt. Circulatory changes involved in body temperature regulation during exercise had little effect on total leg blood flow. Experiments with a foot pedal exercise, with and without occlusion of circulation to the leg, suggest that athletes and trained nonathletes have greater blood flow in the muscles during exercise than do sedentary subjects. In the latter, the first few minutes after exercise without occlusion resembled recovery from exercise with occlusion, indicating that relative ischemia is normal in untrained subjects during moderate exercise.

Submitted on October 19, 1961
Excretion trends in men undergoing deacclimatization to heat
Authors: Hale Henry B. , Ellis James P. , Balke Bruno , McNee Richard C.
Published: December 2017

In an effort to characterize metabolic changes associated with heat deacclimatization under natural conditions, urinary determinations were made on 21 healthy men during the transition period from summer to fall. Two overnight urine specimens per subject per week were analyzed for sodium, potassium, phosphate, urea, uric acid, creatinine, and 17-hydroxycorticosteroids (17-OHCS). No trends were found for urine output, uric acid, urea, or sodium. Creatinine excretion rate and Na/K ratio fell as environmental temperature fell; potassium/creatinine ratio and potassium excretion rate increased. These four variables showed linear trends, but phosphate/creatinine ratio increased in a stepwise manner and urea/creatinine ratio increased only after temperature had fallen far below the summer level. Excretion of 17-OHCS (as rate or ratio) declined (two-stage shift). Subjects who did not exercise regularly showed upward shifting in phosphate excretion; nonexercising subjects as a group showed a cyclic tendency; and those who exercised daily showed essentially no change in phosphate excretion. This retention of one summer characteristic in the latter group is consonant with the literature on heat acclimatization in that it shows that physical fitness is a factor that delays heat deacclimatization.

Submitted on May 25, 1961
Influence of altitude on heart and breathing rates in some Peruvian rodents
Authors: Morrison Peter , Elsner Robert
Published: December 2017

Heart and breathing rates were measured at 0.1 and 4.5 km before, during, and after Nembutal anesthesia in Phyllotis darwini chilensis, P. d. rupestris, P. osilae, P. pictus, Akodon amoenus, A. berlepschii, A. jelskii, and A. boliviensis; in Mus musculus rates were measured at 3.9-4.5 km, and in P. d. limatus, M. musculus, and the white mouse at 0.1 km. None of the high-altitude mice and only the native Phyllotis (+25%) of the low-altitude mice showed a circulatory response to altitude. All the low-altitude mice but only Akodon (+22%) of the high-altitude mice showed a respiratory response to altitude. The native mountain species had higher resting heart and breathing rates than did the lowland forms.

Submitted on October 25, 1961
Effect of lung inflation on bronchial dimensions in the dog
Authors: Marshall Robert
Published: December 2017

Bronchial diameters and lengths were measured from bronchograms of separate lobes of dogs' lungs. The lobes were initially completely airless, and radiographs were taken at intrabronchial pressures of 10 and 20 cm H2O at stages during inflation of the lobe. The bronchi were dissected out, made airtight, and radiographs taken at different distending pressures. In the intact lobe the increase in bronchial diameter occurred mainly at volumes below the functional residual capacity of the lobe. At greater degrees of inflation the diameters increased only slightly and in some cases were reduced. The bronchial lengths increased throughout inflation. Full inflation of the lung caused approximately a 60% increase in bronchial diameter and a 40% increase in bronchial length. Change of intrabronchial pressure from 10 to 20 cm H2O caused only 4% increase in bronchial diameters in the inflated lobe. Comparison with the same diameters in the isolated bronchus showed that the lung parenchyma exerts traction on the bronchial wall but the traction bears no simple relationship to the inflation volume.

Submitted on January 18, 1962
Circulatory and metabolic reactions to work in heat
Authors: Williams C. G. , Bredell G. A. G. , Wyndham C. H. , Strydom N. B. , Morrison J. F. , Peter J. , Fleming P. W. , Ward J. S.
Published: December 2017

Oxygen consumptions were measured at various levels of work up to the individual's maximum. At submaximal work they were significantly lower in heat than in comfortable temperatures, but maximum oxygen intakes were not significantly different. In comfortable conditions cardiac output and A-V difference both contributed to rise in oxygen intake during submaximal work. At maximal effort increase in arteriovenous difference accounted for the ultimate rise in oxygen intake. Both heart rate and stroke volume contributed to increase in cardiac output up to 1.0 liters/min oxygen intake; above this heart rate was the sole factor. In heat the major change in hemodynamics was an increase in heart rate with an associated fall in stroke volume. Neither cardiac output nor arteriovenous difference was significantly altered from comfortable conditions. “Excess” lactate occurred at significantly lower levels of work in heat than in comfortable conditions. Working muscles were therefore relatively more anoxic in heat at submaximal work, and this accounted for lower oxygen intakes. At maximal work the degree of anoxia was the same in both temperature conditions.

Submitted on August 22, 1961
Effect of x-irradiation on Na and K secretion by human parotid gland
Authors: Awwad H. K. , Habib Y. A.
Published: December 2017

Experiments were carried out on 12 subjects to study the secretion of Na and K in the parotid saliva over secretory rates ranging from 0.06 to 2.2 ml/min. The possible effect of X-irradiation per se on such secretions was evaluated. Sodium concentration in saliva was linearly related to flow rate, whereas the potassium concentration was negatively correlated to salivary secretory rate. X-irradiation by itself did not influence the secretion of Na apart from its influence on flow rate. In the case of potassium, a significantly greater regression coefficient of potassium secretion per minute and flow rate was noted. This was associated with a significantly higher K/Na ratio in the saliva.

Submitted on November 13, 1961
Adaptation of thermal pain in the skin
Authors: Greene Leon C. , Hardy James D.
Published: December 2017

Cutaneous pain thresholds were determined on blackened skin of foreheads and forearms of human subjects over areas of 16 cm2 by recording skin temperature during exposure to thermal radiation for periods up to 50 min. Intensity of stimulus was controlled by the subject so that threshold pain was maintained throughout the exposure. After the initial period of adjustment by the subject, radiation intensity was generally maintained constant although skin temperature for the pain threshold decreased from 44.9 C to 43.8 C. By using an intensity as low as 22 mcal/cm2/sec, threshold pain was evoked in 29 min at a skin temperature of 42.2 C. In both groups, once pain had been established it did not disappear. It is inferred from these observations that thermal pain does not adapt for near-threshold stimulation in the period between onset of pain at 30 sec and termination of stimulation.

Submitted on December 26, 1961
Stimulation of ventilation in emphysema by passively induced body motion
Authors: Froeb Herman F.
Published: December 2017

The ventilatory stimulation arising from two different forms of passively induced body motion was chosen for study of 14 male emphysematous subjects with hypercapnia and impaired ventilatory response to carbon dioxide. Nine normal males served as controls. The object of the study was to determine whether the stimulus to ventilation from passive body motion was intact in diseased subjects and whether it could serve as a therapeutic tool by bringing about a reduction in blood carbon dioxide. The results revealed that the stimulus to ventilation was mild and comparable in both groups but was associated with two to three times more oxygen per extra liter of minute ventilation in the diseased subjects. There were no significant changes in the arterial blood gases. It was concluded that the stimulus to ventilation from passive body motion arises from weak muscle action and has no therapeutic application in emphysematous subjects as a means of lowering the PaCOCO2.

Note:

(With the Technical Assistance of Mabel Pearson, Roy Engstrom, Christa McReynolds, and Carol Kennedy)

Submitted on March 5, 1962
Lateral inhibition of heat sensations on the skin
Authors: Békésy G. V.
Published: December 2017

Many of the similarities that have been found between the organ of Corti, the eye, and the vibratory skin sensations are a consequence of lateral inhibition, and these similarities can be extended to heat sensations on the skin also. The chief differences lie in their numerical values. Analogues in heat sensations can be demonstrated for such phenomena as Mach bands and directional hearing, as well as the very pronounced sharpening effects of the spatial distribution of the sensation magnitude for traveling waves.

Submitted on May 16, 1962
Coronary inflow and outflow measurement technique in dogs with thorax intact
Authors: Wcislo Vincent J.
Published: December 2017

A new experimental approach for measurement of blood flow in the main coronary vessels is presented. Using specially devised extracorporeal circulatory loops with flowmeters and temporary cannulation of coronary arterial and venous orifices with large-bore, stiff catheters, the coronary blood flow was measured in dogs under almost normal conditions. In heparinized, large dogs under light pentobarbital anesthesia, coronary inflow was determined by directing the blood from the femoral artery through an arterial external loop and a Cybulski blood flowmeter to a one-channeled catheter, introduced via the common carotid artery into the aorta and temporarily wedged into the orifice of the left or right coronary artery. Simultaneously, the coronary sinus outflow was measured by inserting a two-channeled catheter into the sinusal orifice via the external jugular vein and right atrium. The catheter blocks this orifice and diverts the outflowing blood, first to the venous external loop, and then directs the return of the blood through a second flowmeter to the right atrium. Coronary flow and other cardiovascular functions were measured and optically recorded. The experiments did not necessitate subsequent sacrifice of the animals.

Submitted on April 9, 1962
Neural factors underlying variations in electrical resistance of apparently nonsweating skin
Authors: Thomas P. E. , Kawahata Aikoh
Published: December 2017

Many investigators have demonstrated that sympathetic sudomotor activity sufficient to cause visible sweating is accompanied by a decrease in electrical skin resistance (ESR). Furthermore, the reciprocal of resistance (conductance) was shown to be linearly related to the amount of perspiration and the number of visibly active sweat glands. The present study examines the relationship of ESR to sweat-gland activation under apparently nonsweating circumstances, and clarifies the significance of topographical differences in ESR observed in human studies conducted at moderate (nonsweating) temperatures; results also suggest a neural influence on insensible perspiration. Comparisons in adjacent high- and low-resistance areas were made of the sweat gland responses produced by intradermal injections of drugs that directly stimulate sweat glands. When just-threshold quantities of acetylcholine (ACh), pilocarpine, or epinephrine were used, the low-resistance areas always responded with more numerous activated glands. When both high- and low-resistance areas were injected with procaine approximately 10 min prior to ACh injection, activated sweat gland response was essentially similar in both areas. At moderate temperatures, sweat glands evidently receive sudomotor impulses at a rate that does not produce visible sweating, but does increase transcutaneous water transfer and electrolyte conductance

Submitted on February 21, 1961
Regulation of respiration and heart rate response in exercise during altitude acclimatization
Authors: Dejours Pierre , Kellogg Ralph H. , Pace Nello
Published: December 2017

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

Submitted on February 5, 1962
A mathematical approach to hemodialysis
Authors: Yoder Richard D.
Published: December 2017

Hemodialysis may be investigated by utilizing a laboratory system composed of a reservoir, hemodialysis unit, and bath solution. The effect of the Kolff-type dialysis unit is to permit diffusion of solute and to filter solvent and solute while pressure decreases along the length of its tubing. Kinetic equations in which the length of the dialysis tubing is the independent variable describe these processes in terms of the gradients of pressure, solvent flow rate, and solute concentration. Changes of volume and solvent concentration in the wash and reservoir solutions are functions of time and of the net effect of the dialysis unit at a given time. The complete set of general equations describes the behavior of the system. Functions for the equations of the wash and reservoir solutions are easily derived. An inflatable ellipse is selected as an appropriate geometric shape for the cross section of the dialysis tubing and functions are derived for the equations of the dialysis unit.

Submitted on March 9, 1962
Reflex pulmonary hypertension of fresh-water aspiration
Authors: Colebatch H. J. H. , Halmagyi D. F. J.
Published: December 2017

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

Submitted on May 7, 1962
Species difference in pancreatic lipolytic and amylolytic enzymes
Authors: Zieve Leslie , Vogel William C. , Kelly William D.
Published: December 2017

The pancreatic content of lecithinase A in man is approximately 10–20 times that in the dog. In contrast, the pancreatic content of lipase is one-half and of amylase one-sixth that of the dog. The rabbit is similar to man in its pancreatic amylase and lipase content, and to the dog in its lecithinase A content. In man the serum lecithinase A increases during acute pancreatitis, paralleling more or less the elevations in serum amylase and lipase. Though individual discrepancies are noted, all three enzymes increase roughly proportionately. During acute pancreatitis in the dog, the serum lecithinase A increases but slightly, in sharp contrast to the elevations in serum amylase and lipase which are greater than in man.

Submitted on July 12, 1962
Frequency components and positional changes in electrocardiogram of the adult rat
Authors: Angelakos Evangelos T. , Bernardini Pamela
Published: December 2017

Standard limb electrocardiograms of the adult rat (4–5 months old) were studied using cathode-ray oscillographic techniques. Fourier analysis revealed that the main QRS components can be represented with sine-wave frequencies of 50–400 cycles/sec. Gross distortion was observed with filters providing a high-frequency response of less than 250 cycles/sec. The mean QRS axis was found to be quite sensitive to positional changes.

Submitted on August 8, 1962
In vivo activation of the fibrinolytic enzyme system of dogs
Authors: Taylor Fletcher B. , Singleton John , Bickford Arthur F.
Published: December 2017

We studied the effect of streptokinase and small amounts of human plasmin on the components of the fibrinolytic enzyme system of the dog. A 1-hr infusion of streptokinase (500 U/ml blood volume) and plasmin (.001 mg/ml blood volume) in dogs produced during the infusion: 1) No adverse immune reaction. 2) Enhanced lysis of blood clots. 3) Decreased serum plasminogen and plasma plasmin inhibitor levels. 4) Decreased plasma fibrinogen levels. The clot lysis rates, plasminogen, and plasma plasmin inhibitor levels returned to one-half their preinfusion level within 4–8 hr. The fibrinogen level returned to one-half its preinfusion level after 12 hr.

Submitted on September 10, 1962