bluuebunny/crossref_metadata_2025 huggingface dataset:
Circulating plasma volume changes in anesthetized dogs during positive pressure breathing
Authors: Sobel S. , Marotta S. F. , Marbarger J. P.
Published: December 2017

Various circulatory functions were measured in anesthetized dogs subjected to 18.5 mm Hg positive pressure breathing. Immediately upon raising the intrapulmonary pressure there occurred a five- to sixfold increase in venous pressure as well as a decrease in mean arterial pressure. Accompanying these pressure changes was a progressive decrease in circulating plasma volume as measured by the T-1824 method. A 30% decrease in plasma volume was recorded after 160 minutes of increased intrapulmonary pressure. Hemoconcentration was also indicated by the increased hematocrits, although calculated fluid loss was only 13%. All circulatory changes returned to prepressure breathing levels upon release of pressure breathing. Other changes, such as oliguria, periods of apnea and an alkaline urine accompanied positive pressure breathing. The data suggest that the decrease in plasma volume is the result of venostasis caused by the rapid increase in venous pressure.

Submitted on April 27, 1959
Respiratory and cerebral circulatory control during exercise at .21 and 2.0 atmospheres inspired pO2
Authors: Lambertsen Christian J. , Owen S. G. , Wendel Herbert , Stroud Morris W. , Lurie Abraham A. , Lochner Wilhelm , Clark Gordon F.
Published: December 2017

Respiratory and cerebral hemodynamic responses to leg exercise during respiration of air at 1.0 atm. and O2 at 2.0 atm. were studied in relation to changes in arterial and internal jugular venous blood oxygen composition, pH, pCO2 and bicarbonate concentration. The hyperpnea of exercise at 1.0 atm. was accompanied by arterial and venous acidemia and hypocapnia. Oxygen administration during exercise at 2.0 atm. lowered ventilation, restored arterial pH and pCO2 toward resting levels and caused venous pCO2 to rise above the resting level; cerebral venous cH remained elevated in spite of reduction of blood fixed acid concentration. The ventilatory response to exercise showed positive correlations with work load, oxygen consumption, and with changes in arterial and internal jugular venous cH and fixed acid. The observed negative correlations of changes in respiratory minute volume with changes in arterial and internal jugular venous pCO2 and bicarbonate concentration suggest that these factors are functions, rather than primary determinants, of ventilation in exercise. Cerebral hemodynamics and oxygen consumption were not significantly altered by exercise at 1.0 atm. The data suggest either a slight elevation of cerebral blood flow or reduction in the rate of cerebral oxygen consumption during exercise breathing O2 at 2.0 atm., without gross elevation of cerebral venous pO2. Observed changes in cerebral vascular resistance during exercise at .21 and 2.0 atm. inspired pO2 appear related to concomitant alterations in arterial pCO2, with no detectable relationship either to brain oxygen requirement of cerebral venous acid-base composition.

Submitted on November 25, 1958
Effect of environmental temperature on metabolic changes following physical injury
Authors: Haist R. E. , Hawkins Rosemary D. , Kovacs Georgine V.
Published: December 2017

Rats in shock resulting from limb ischemia showed no significant differences in the rise in blood nonprotein nitrogen when kept at different environmental temperatures after the period of limb ischemia. Under these conditions the elevation in blood inorganic phosphorus was inversely related to the environmental temperature. In the shocked rats the tolerance for orally administered carbohydrate was less and the hepatic glycogen values were higher at 21°-32°C than at 10°C. However, at similar times the residue of reducing substances in the gut was greater at 10°C than at 21°-32°C. There was no significant difference in the tolerance for intravenously administered glucose at 10°, 20° and 30°C in the shocked rats, but control rats, with clamps left in position, showed a significantly better tolerance at 10°C than at 20° or 30°C. Under the conditions used, environmental temperature had little influence on blood N.P.N. changes in shock, but did influence the blood inorganic phosphorus levels and the tolerance for orally administered carbohydrate.

Submitted on July 16, 1959
Correlation of pulmonary function and domestic microenvironment
Authors: Shephard Roy J. , Turner M. E. , Carey G. C. R. , Phair J. J.
Published: December 2017

Pulmonary pressures, total and timed vital capacity, functional residual capacity and carbon monoxide uptake have been correlated with temperature, humidity, suspended particulate matter and gaseous acid in a 3-month prospective survey of 10 cardiorespiratory cripples. Results have been analyzed by a sequential multiple regression technique, and significant relationships demonstrated between pulmonary function measurements and time, humidity and suspended particulate matter. The immediate response to suspended particulate matter was consistent with bronchoconstriction, although the most significant features were a transient depression of pulmonary pressures and carbon monoxide uptake. The prolonged depression of carbon monoxide uptake, starting 4 days after an intense episode of pollution, did not show itself as a significant long-lag coefficient for the survey as a whole; the existence of a threshold dose of suspended particulate to produce structural damage is postulated.

Submitted on February 20, 1959
Effect of pulmonary artery occlusion upon end-tidal CO2 tension
Authors: Julian Desmond G. , Travis David M. , Robin Eugene D. , Crump Charles H.
Published: December 2017

Occlusion of branches of the pulmonary artery has been performed in dogs to determine its effect upon the relationship between peak end-tidal and arterial carbon dioxide tension. The use of the formula (See PDF) to express the percentage of alveolar space which is ventilated but not perfused has been tested by its application to the values encountered when one main pulmonary artery is occluded and when a smaller branch is occluded. This formula is found to express approximately the percentage unperfused.

Submitted on August 15, 1958
Effect of exercise, immobilization and intermittent stretching on strength of knee ligaments of albino rats
Authors: Rasch Philip J. , Maniscalco Ruth , Pierson William R. , Logan Gene A.
Published: December 2017

Sixty male albino rats were divided into four groups. The rats in the first group were exercised; those in the second were subjected to intermittent passive stretching of one hind leg; those in the third group had one hind leg immobilized; those in the fourth group served as controls. At the end of 4 weeks, all animals were sacrificed and the muscle tissue was dissected from the hind legs. The limbs were then torn apart at the knee joint. No significant differences were found in the amount of stress required to tear the knee ligaments in the various groups.

Submitted on September 29, 1959
Mechanical work of breathing during muscular exercise
Authors: Margaria R. , Milic-Emili G. , Petit J. M. , Cavagna G.
Published: December 2017

The mechanical work of breathing was measured during muscular exercise on three normal subjects from simultaneous records of intra-esophageal pressure and tidal volume. At the maximal values of ventilation attained during exercise, the mechanical work of breathing amounts to about 100–120 cal/min. The maximum pulmonary ventilation useful for external work is attained when the energy cost of breathing due to any additional unit of air ventilated (dWre/dV) equals the additional energy provided by the same change in ventilation (dWtot/ dV), i.e. when dWre/dV = dWtot/dV. The maximal values of ventilation obtained experimentally during muscular exercise are in good agreement with that assumption, if the mechanical efficiency of the respiratory muscles is taken as 0.25. This implies that the mechanical efficiency of the respiratory muscles is the same as that of the muscles involved in performing useful external work. The work of breathing is of relatively small magnitude: during exercise the work of a breathing cycle amounts, at maximum, to 8% of the maximum potential work of breathing, calculated from the pressure-volume diagram of the respiratory apparatus, and the energy cost of respiration represents no more than 3% of the total energy consumed by the subject.

Submitted on May 21, 1959
Effects of conditioning on the ballistocardiogram of college basketball players
Authors: Montoye Henry J. , Collings W. Doyne , Stauffer Gordon C.
Published: December 2017

This study was undertaken to investigate the effects of vigorous athletic training on the ballistocardiogram. Ten varsity college basketball players were tested twice before the season began, twice during the season, and once from 4 to 6 weeks after the season was concluded. Ballistocardiograms were recorded before and after a standard exercise at each testing period. While the heart rates, particularly after the standard exercise, decreased with training, there was no statistically significant effect of training on the ballistocardiogram. This was thought to be due to limitations of the direct-body ballistocardiograph, particularly as influenced by changes in skin-fold fat of the subject. The immediate effects of exercise were an increase in amplitude and areas of the I plus J waves and the amplitude of the K wave. No immediate effects of exercise or of training were observed on the I-J or J-K intervals or on the respiratory effects on the ballistocardiogram.

Submitted on October 1, 1959
Comparison of dye-dilution and flowmeter estimates of pulmonary valve incompetence in dogs
Authors: Korner P. I. , Uther J. B. , Chalmers J. P. , Nicks R.
Published: December 2017

Quantitative estimates of backflow were obtained in dogs with experimental pulmonary valve incompetence by means of a bristle flowmeter and the dye curve variance method. The variance of the curve was found to be the best index of indicator dispersion and is calculated from analogy to a frequency distribution curve. The method postulates that (forward flow + backflow)/forward flow = variance observed during incompetence/Vx(F; V), where Vx(F; V) is the expected variance for the same forward flow and volume between injection and sampling sites and is determined from regression equations calculated from data of normal dogs. There was good agreement between dye and flowmeter results, provided that Vx(F2;V) was estimated for the specific regression equations obtained from individual dogs. Three or four successive dye curves, obtained while the animal was in a steady state, permitted quantitation of backflow with the accuracy of a single determination of forward flow by the direct Fick or dye method. When Vx(F;V) was estimated from regression equations obtained from the pooled data and normal dogs, agreement with the flowmeter estimates was poor.

Submitted on October 28, 1959
Manual performance as a function of rate of change in hand skin temperature
Authors: Clark R. Ernest , Cohen Alexander
Published: December 2017

Manual performance (knot tying) was studied as a function of fast and slow rates of cooling during cold exposure and during subsequent rewarming. It was found that performance decrements accompanying cold exposure were sizeably increased as the rate of cooling decreased. These increased decrements associated with slow cooling perseverated even after the hands had been rewarmed to precooling temperatures. In addition, the results indicated a direct relationship between rate of cooling and rate of rewarming.

Submitted on November 30, 1959
Pulmonary capillary blood volume, flow and diffusing capacity during exercise
Authors: Johnson R. L. , Spicer W. S. , Bishop J. M. , Forster Robert E.
Published: December 2017

Pulmonary capillary blood flow (Qc) and apparent CO diffusing capacity (Dl) were calculated from the rates of disappearance of small alveolar concentrations of inspired acetylene and carbon monoxide during breath holding. Such measurements were performed simultaneously in four normal subjects at rest, during exercise and while performing Valsalva or Mueller maneuvers; they were also made at more than one alveolar oxygen tension so that true membrane diffusing capacity (Dm) and pulmonary capillary blood volume (Vc) could be calculated by the method of Roughton and Forster. Dl, Dm and Vc were closely correlated with Qc (r = 0.92, 0.71 and 0.92, respectively), indicating that both volume and effective surface of the pulmonary capillary bed changed along with corresponding directional changes in blood flow. During transients after starting or after stopping exercise, changes in Dl lagged slightly behind the associated changes in Qc; both parameters tended to reach steady values, however, after about 1 minute of steady exercise. The average time spent by red cells in the pulmonary capillaries at rest was estimated to be 0.79 second, falling to about 0.5 second at levels of exercise at which volume flow through the capillary bed was approximately tripled.

Submitted on September 18, 1959
Vagal inhibition of the heart in deep hypothermia
Authors: Adolph E. F. , Nail R. L.
Published: December 2017

Rats were cooled to 16°C esophageal temperature; the vagi were exposed. As the rats were further cooled one vagus was stimulated to produce bursts of impulses of varying frequencies. At low temperatures a lesser frequency of vagal stimulation and a greater intensity were required to produce inhibitory vagal impulses than in euthermia. Electrocardiographic tracings recorded the heart beats. Vagal impulses sharply decreased the heart frequency at all temperatures down to 12°C. Between 12° and 8°C the effect disappeared reversibly. Atropine blocked the vagal effect at the low body temperatures (16°C) as well as at high ones. Evidently vagal impulses may affect the heart rate at temperatures nearly as low as those at which the heart ceases to beat.

Submitted on April 4, 1960
Physiological index of strain and body heat storage in hyperthermia
Authors: Hall John F. , Polte J. W.
Published: December 2017

Individual variability of a modified Craig index of physiological strain and body heat storage was determined, and the relationship between these parameters defined for five healthy, nonacclimatized male subjects exposed five times to each of three heat stress levels: 38°C, 54°C and 71°C at a vapor pressure of 10 mm Hg. This index contains the variables of heart rate, sweat rate and rate of rectal temperature change, measured by EKG, nude pre- and post-experimental weighings, and a rectal thermistor, respectively. Body heat storage was calculated from initial and terminal weighted mean skin and rectal temperatures. Subjects were sitting and wore 1 clo of body insulation. Individual and group variation for strain index and body heat storage was determined. The data show a linear relationship between these expressions over the thermal stress range investigated although individual variability was considerable at the higher stress levels. A statistically significant correlation between strain index and body heat storage is shown.

Submitted on May 16, 1960
Blood-borne vasodilating agent from ischemic tissues
Authors: Freeburg B. R. , Hyman Chester
Published: December 2017

Plethysmographic measurements of forearm blood flow show a drop to minimal values immediately after release of arterial occlusion of a leg; this is soon followed by a somewhat greater and more sustained increase to values above the control. Prepacking the leg with blood before arterial occlusion, or exercise before occlusion, or a combination of these procedures does not significantly alter the response. Calculated peripheral resistance in the forearm follows the pattern implied by the blood flow changes. It is suggested that the initial vasoconstriction is a reflex whereas the later vasodilatation is due to a stable, circulating agent from the previously ischemic leg.

Submitted on April 29, 1960
Serum elastase inhibitor levels in pregnancy and under endocrine influences
Authors: Schneider Robert B. , Walford Roy L. , Dignam William J.
Published: December 2017

Serum elastase inhibitor is significantly elevated during pregnancy both in the human and in the rat, but not in the rabbit. In humans the change is progressive, reaching an average value by parturition of three times the value for nonpregnant women or for 6 weeks postpartum women. Injection of ACTH, progesterone, and estrogen separately into nonpregnant female rats failed to produce significant or corresponding alterations in serum elastase inhibitor levels in these animals.

Submitted on July 5, 1960
Physiological reactions of men and women during muscular activity and recovery in various environments
Authors: Brouha L. , Smith P. E. , De Lanne R. , Maxfield M. E.
Published: December 2017

Men and women performing a standard exercise were studied in three environments. Pulmonary ventilation, O2 consumption, CO2 elimination, heart rate, blood pressure, body temperature and weight loss were recorded. Pulmonary ventilation was usually decreased in the warm-dry environment and increased in the warm-humid. Oxygen consumption was significantly lower in the warm-dry environment than at room temperature. The pattern of changes of these two functions was similar for both sexes. Respiratory exchange ratios were not influenced by sex, but were higher in the warm-dry environment. Increase in body temperature was found only in the warm-humid environment, with a smaller weight loss than in warm-dry conditions. Systolic blood pressure was influenced by work load but not by environments. Diastolic pressure varied little for both sexes under all conditions. Heart rate was significantly influenced by sex and environment, being highest for the women in the warm-humid conditions. Cardiac cost increased and cardiac efficiency decreased in both warm surroundings, more so for women than for men.

Submitted on May 16, 1960
Effects of relatively high accelerations on some biological systems
Authors: Slonim Arnold R.
Published: December 2017

Fasting male subjects were exposed to forward accelerations (12-degree back angle) at fatiguing levels varying both in amplitude and duration, nonfatiguing levels and mock runs, and to treadmill exercise. The following analyses were made: plasma bicarbonate, blood glucose, phosphorus and creatinine, urine creatinine, urine volume, urinalysis, and an estimate of creatinine clearance. The only consistent change noted after fatiguing accelerations was a small rise in blood creatinine ( P < 0.05). Exercise, however, resulted in a marked ( P < 0.01) decrease in bicarbonate, rise in blood creatinine, and drop in clearance. Accelerations in comparison to exercise showed little effect on either muscular or renal activity. No correlation was found between any of the biochemical measurements and acceleration intensity nor were there any differences noted between real and mock accelerations, indicating that none of these tests could index the severity of accelerative stress. The fatigue associated with high accelerations is not easily explainable in terms of increased muscular activity.

Submitted on August 3, 1960
Isotope external counting method for cardiac output analyzed in glass model circulation
Authors: Gorten Ralph , Gunnells J. Caulie
Published: December 2017

Certain aspects regarding degree of accuracy and some of the theoretical sources of error of the isotope-external counting method for determination of cardiac output have been further evaluated by the use of a glass model central circulation. By comparing calculated flow with actually timed flow, and by observing the constant relationship between dilution curve area and flow, it was found that single as well as multichambered systems could be used for this method with valid and reproducible results. Variations in chamber size, rate of flow, isotope dosage and instrument settings were used to evaluate some of the possible sources of error. Variable mixing was the most important factor responsible for discrepancies. Errors in extrapolation of the primary dilution curve to zero and instrumental lag were considered to be of less importance and can most often be avoided. A change in the recording time constant altered the curve shape, and therefore the calculated mean transit time, but not curve area and calculated flow.

Submitted on July 6, 1960
Effect of norepinephrine on plasma free fatty acids level in man
Authors: Klein Robert F. , Estes E. Harvey , Bogdonoff Morton D.
Published: December 2017

Plasma free fatty acid (FFA) and glucose levels were measured in 44 young male subjects who received intravenous infusions of norepinephrine. Dose levels and rates of infusion were independently varied. A significant dose-response relationship was noted for FFA. The time at which the peak response occurred depended on the duration of infusion. A postinfusion fall in FFA level was observed, which suggests that exogenous infusion of norepinephrine may inhibit endogenous lipid-mobilizing mechanisms.

Submitted on October 11, 1960
Steroid pyrogen studies in laboratory and domestic animals
Authors: Palmer Robert H. , Ratkovits Bela , Kappas Attallah
Published: December 2017

The 5β-H steroid hormone metabolites, etiocholanolone (3α-hydroxyetiocholan-17-one), pregnanolone (3α-hydroxypregnan-20-one) and 11-ketopregnanolone (3-hydroxypregnan-11, 20-dione) were administered by intramuscular, intravenous and intrathecal injection in doses of 1.0 and 5.0 mg/kg body weight to various species of animals including cats, dogs, rats, mice, guinea pigs, rabbits, monkeys, sheep, steers, burros and pigs in order to determine whether these species were susceptible to the pyrogenic action of steroids. In addition, certain animals received injections of the 5-H steroid metabolite, androsterone (3α-hydroxyandrostan-17-one). None of these animals developed pyrogenic responses to these steroid hormone transformation products indicating that the fever-producing action of 5β-H steroid metabolites previously noted in human beings is apparently a form of biological activity which is highly species specific.

Submitted on November 16, 1960
Relationship between body fat and shivering in air at 15 C
Authors: Daniels Farrington , Baker Paul T.
Published: December 2017

Thirty-one men of widely varying body fat content were exposed to air at 15.2 C for 2 hr. Rectal and skin temperatures and metabolic rates were measured at 10, 40, and 80 min and at the end of the 2 hr. Shivering was rated on a five-interval scale. Under these conditions thick subcutaneous fat provided insulation as indicated by lower skin temperatures, less shivering, and lower oxygen consumption in the fatter men. The findings rule out simple relationships between measured temperatures and shivering, leading to other possibilities and approaches to the study of shivering.

Submitted on October 3, 1960
Relation between alveolar surface tension and pulmonary vascular resistance
Authors: Thomas Lewis J. , Roos Albert , Griffo Zora J.
Published: December 2017

In order to examine the hypothesis that surface forces at the alveolar air-liquid interface may play a role in determining the course of pulmonary vascular resistance on negative-pressure inflation, resistance was studied as a function of lung volume for both air and dextran-filled dog lungs in excised preparations perfused with fresh dog blood under carefully controlled conditions. Results show that abolishing the interface by liquid filling does not alter the course of resistance significantly. It is thus concluded that the presence of the interface can have only a minor effect on the course of resistance and that purely volume-dependent factors are primarily responsible.

Submitted on September 19, 1960
Elevation gradient of intrathoracic pressure
Authors: Krueger John J. , Bain Thomas , Patterson John L.
Published: December 2017

Intrathoracic (intrapleural) pressure was measured in 15 anesthetized mongrel dogs held in the vertical position. A small balloon attached to a polyethylene catheter was inserted, without admission of air, into the chest through the 3rd intercostal space, or above the first rib, and passed down to the costophrenic sulcus. Along the lateral, anterolateral, and posterolateral aspects of the lung surface a vertical gradient of pressure was found, amounting to an increase of +0.21 cm H2O/cm descent, which was absent when the animal was in the horizontal position. This pressure gradient agrees closely with the gradient predicted on the basis of the mean density of lung tissue at end expiration in these animals. Among the implications of these findings is the possible existence of regional differences in the elastic work of breathing, based on differences in vertical distance between parts of the lung.

Submitted on May 2, 1960
Blood distribution during cardiac arrest induced by hypothermia
Authors: Willard Paul W. , Horvath Steven M.
Published: December 2017

Blood volumes with simultaneous blood- and red cell-distribution measurements were determined by the Cr51 technique in four groups of rats. In splenectomized and nonsplenectomized animals, blood volume of the whole body, lung, spleen, liver, kidney, heart, diaphragm, and gastrocnemius muscle was measured in both the control rats (body temperature 37 C) and in rats with hypothermically induced cardiac arrest (body temperature 8–9 C). Splenectomy caused alterations in some visceral blood volumes without concurrent changes in red cell mass. With cardiac arrest increased quantities of blood and red cell mass were observed in the lung, liver, and gastrocnemius in both splenectomized and nonsplenectomized groups. In the nonsplenectomized animals an increase of over 100 % in spleen blood volume was observed. When the two hypothermic groups were compared, differences existed only in blood volume of the lung, heart, and kidney. Hypothermia induced a pattern of blood redistribution toward visceral areas of the body.

Submitted on October 14, 1960
A trapezoidal-wave electromagnetic blood flowmeter
Authors: Yanof Howard M.
Published: December 2017

A new, electromagnetic blood flowmeter is described which has been designed to provide the physiologist with a reliable instrument allowing the measurement of blood flow in the unbroken blood vessel. The transducer has been made small enough to allow implantation in the animal for relatively long periods of time. In this way the flow in a number of vessels can be measured simultaneously in the unanesthetized animal. This flowmeter is different from existing flowmeters because of the unique trapezoidal-wave current that energizes the magnet. A method for calibrating the instrument is described and data is presented showing the femoral artery flow in response to epinephrine and norepinephrine, and hepatic artery flow in response to norepinephrine.

Note:

(With the Engineering Assistance of Paul Salz)

Submitted on January 16, 1961
Effect of uneven ventilation on pulmonary diffusing capacity
Authors: Lewis Benjamin M. , Hayford-Welsing E. J. , Furusho Akio , Reed L. C.
Published: December 2017

In four normal subjects measurements of steady state diffusing capacity for CO (DLCO) by an alveolar sample technique and of the degree of uneven ventilation by nitrogen washout were made simultaneously followed by measurement of DLCO by rebreathing. A methacholine-histamine aerosol was then given. After this aerosol uneven ventilation worsened and steady state DLCO fell, while rebreathing DLCO did not change. Relief of uneven ventilation by isoproterenol was followed by increase of steady state DLCO in two subjects. Alterations in rate and depth of breathing or changes in functional residual capacity do not explain the changes in steady state DLCO which are attributed to increase in uneven ventilation as predicted by the theory of CO absorption. Theory also predicts a lack of effect of uneven ventilation on the rebreathing DLCO, but these results must be accepted with caution because deep breathing may reverse the effects of the methacholine-histamine aerosol and O2 consumption during rebreathing rises after this aerosol.

Submitted on December 30, 1960
Pulsatile gas flow in bronchi caused by the heart beat
Authors: West J. B. , Hugh-Jones P.
Published: December 2017

Pulsatile gas flow in lobar and segmental bronchi synchronous with the heart beat has been measured during routine diagnostic bronchoscopy, using a new type of flowmeter. Pulsations were detected in three-quarters of the 60 patients examined, and occurred in all parts of the lung though they were more marked on the left side. They were seen both during inspiration and expiration, but were most obvious in the postexpiratory pauses. At a given instant in the cardiac cycle, the phase of the pulsations was sometimes different in different parts of the lung, gas going into some lobes and coming out of others. Volume flow rates up to 2.5 liter/min and displaced volumes up to 5 ml were recorded. The pulsatile flow is probably caused by changes in volume of the beating heart, and by its movements within the chest so that some parts of the lung are compressed while others expand. Because of their size and frequency, the pulsations promote mixing of the anatomical dead-space gas with alveolar gas.

Submitted on October 10, 1960
Vascular and sweating responses to regional heating of the body surface
Authors: Rawson Robert O. , Randall Walter C.
Published: December 2017

The significance of cutaneous and internal thermoreceptors in human temperature regulation was studied by exposing the subject simultaneously to environmental temperatures of 25 and 60 C. Cutaneous, rectal, and tympanic membrane temperatures were recorded along with sudomotor and vasomotor responses. Heat stress to the lower half of the body was accompanied by marked differential vasomotor responses and a pronounced caudal-to-rostral recruitment of sweating in spite of an unchanging or declining tympanic membrane temperature. Heating the upper half resulted in essentially the same vasomotor and sudomotor responses but with significant alteration in the time course and intensity of the sweat recruitment pattern. With sudden lowering of the ambient temperature, sweating on all areas disappeared while internal temperatures remained unchanged. It is clearly demonstrated that under the given experimental conditions both cutaneous and internal thermoreceptors play a significant role in human temperature regulation and that the hypothalamus is not the sole moderator of internal temperature control.

Submitted on July 16, 1961
Age-related changes in erythrocyte agglutinability in Hiroshima subjects
Authors: Hollingsworth J. W. , Hamilton H. B. , Ishii G.
Published: December 2017

As part of a physiologic aging assessment in survivors of the atomic bombing, agglutinability of erythrocytes with A and B antisera was studied in 1,495 subjects in Hiroshima. It was found that erythrocyte agglutinability is maximal during the third decade and falls progressively with advancing years. At age 20—40, agglutinability of erythrocytes from females was somewhat less than that of males. Subjects of blood group AB demonstrated agglutinability titers with both antisera comparable to the titers of the group A and B subjects. Analysis of agglutinability titers in relationship to degree of irradiation from the Hiroshima atomic bomb in 1945 failed to show differences, but the sample was too small to allow definite conclusions about possible radiation-accelerated aging.

Note:

With the Technical Assistance of N. Ueda

Submitted on February 16, 1961
Oxygen uptake during the first minutes of heavy muscular exercise
Authors: Åstrand Per-Olof , Saltin Bengt
Published: December 2017

Oxygen uptake, heart rate, pulmonary ventilation, and blood lactic acid were studied in five subjects performing maximal work on a bicycle ergometer. After a 10-min warming up period work loads were varied so that exhaustion terminated exercise after about 2—8 min. Peak oxygen uptake and heart rate were practically identical (sd 3.1% and 3 beats/minute, respectively) in the experiments. The heavier the work was and the shorter the work time the higher became the pulmonary ventilation. There was a more rapid increase in the functions studied when the heaviest work loads were performed. It is concluded that aerobic capacity can be measured in a work test of from a few up to about 8 min duration, severity of work determining the actual work time necessary. Duration of work in studies of circulation and respiration during submaximal work should exceed 5 min.

Submitted on June 23, 1961
Interpretation of radioactive gas clearance rates in the lung
Authors: West J. B. , Holland R. A. B. , Dollery C. T. , Matthews C. M. E.
Published: December 2017

The clearance rates of short-lived radioactive gases from defined areas of the lung have been used to measure regional blood flow and gas exchange. The clearance rates are measured by external counting over the chest during a short period of breath holding following a rapid inspiration of the gas. Two processes are necessary for the clearance of any radioactive gas from the counting field, namely, transfer from alveolar gas to pulmonary capillary blood, and subsequent removal of the active gas from the field. Recently it has been shown that oxygen-labeled CO2 is lost from alveolar gas exceedingly rapidly, and it can therefore be used to separate these two clearance rate processes. A theoretical analysis shows how that can be done, and experiments designed to test the theory are described. Although considerable approximations are necessary, the analysis clarifies the factors controlling the clearance rate of any radioactive gas. One consequence is that the large variations in the regional uptake of radioactive CO and O2 previously reported are probably overestimates.

Submitted on December 7, 1960
Heart sounds of healthy Macaca mulatta
Authors: Hamlin Robert L. , Robinson F. R. , Smith C. R. , Marsland William P.
Published: December 2017

Heart sounds were recorded from 13 healthy Macaca mulatta. The first heart sound began 0.036 sec after onset of QRS. Mean duration was 0.074 sec with an average of 6.4 vibrations. The period of systole was silent in all animals, and had a mean duration of 0.190 sec. The second heart sound was lower in magnitude than the first. Mean duration was 0.038 sec, with an average of 3.5 vibrations. The period of diastole was silent in nine animals and exhibited low frequency vibrations throughout the entire period in four animals. The average duration of diastole was 0.157 sec.

Submitted on August 16, 1961
Mechanical function of the main pulmonary artery
Authors: Patel Dali J. , De Freitas Flavio M. , Mallos Alexander J.
Published: December 2017

The relationship among the longitudinal strain, circumferential strain, lateral intravascular pressure, blood flow, and longitudinal motion was examined in the main pulmonary artery of living, open-chested dogs. Results indicate: 1) The mean value for longitudinal extensibility was 0.73% change in length per centimeter of water pressure (± .19 sd ± .04 sem). 2) The mean value for volume distensibility was 2.28% change in volume per centimeter of water pressure (± .9 sd ± .17 sem). 3) The magnitude of the radial vessel wall velocity is small. 4) The magnitude of the longitudinal vessel wall velocity, though small over most of the cardiac cycle, may become significant at the beginning of cardiac systole, especially during isoproterenol administration.

Submitted on October 3, 1961
Effects of fat emulsion on O2 transport and alveolar-arterial gas tensions
Authors: Cain Stephen M.
Published: December 2017

Ten dogs were made progressively hypoxic by rebreathing from an air-filled spirometer. Arterial blood samples were drawn at five levels of alveolar Po2 (100, 70, 55, 40, and 25 mm Hg), as well as samples before and after the hypoxia for O2-capacity determinations. Half the animals then were given 25 ml/kg of fat emulsion intravenously and the others were given the same amount of dextran. The same sampling procedure was repeated and the blood was analyzed for O2 content. In separate experiments, the same procedure was followed for five dogs but only fat emulsion was given and the arterial blood was analyzed for Po2 and Pco2. Oxyhemoglobin dissociation curves were constructed from the values of saturation at progressively falling alveolar o2. These were transformed into a linear equation by the Hill equation and treated statistically. No significant differences were found between any of the comparisons of slope or displacement. It was concluded that lipemia offered no practical hindrance to the uptake of O2 by the red cell. Alveolar-arterial gas tension differences revealed no change after intravenous fat emulsion in the Po2 difference, but there was a threefold increase in the Pco2 difference.

Submitted on June 12, 1961
Gas composition of pressurized, perfused gas pockets and the fish swim bladder
Authors: Piiper J. , Humphrey H. T. , Rahn H.
Published: December 2017

The behavior of the composition of pressurized, perfused gas pockets is analyzed in theory and experimentally, with the aim of contributing to the understanding of the effect of differential absorption on the composition of the fish swim bladder gas. The equations describing the change in the composition of pressurized, perfused gas pockets are derived and experimentally verified. If a gas pocket initially containing room air is subjected to elevated pressure and perfused with water equilibrated with room air, the concentration of the less soluble gas nitrogen increases during the absorption process. High partial pressures of nitrogen and argon found in swim bladders of fish living at great depths can be qualitatively explained on the basis of accumulation of these gases by preferential absorption of oxygen and carbon dioxide, in connection with certain assumptions on the mode of secretion of the gases

Submitted on October 9, 1961
Measurement of the thermal pain threshold of the hard palate
Authors: Margarida R. , Hardy J. D. , Hammel H. T.
Published: December 2017

Using thin-walled aluminum thermodes individually fitted to the roof of the mouth, the pain threshold of the hard palate was measured in four subjects. By rapidly circulating hot water and water at 37 C alternately, the temperature of the thermode could be raised and lowered between a neutral and a test level. Temperature within the thermode was measured in every observation by a fine wire thermocouple in the circulating water. Temperature between the thermode and the hard palate was also measured over the entire range of temperatures studied, and a correction for the gradient across the thermode wall was determined and applied to the water temperature. Stimuli between 40 C and 49 C were administered. Each subject was exposed to 288 stimuli in six experimental periods. The range of stimuli reported as painful was from 44.5 C for the first reports of pain to 47.7 C which always evoked pain. A preliminary study was made of the buccal temperature changes occurring during drinking hot beverages, and evidence indicates the sipping of air with small amounts of the hot liquid maintains the tissue temperatures within tolerable limits.

Submitted on November 22, 1961
Diffusing capacity of the lung for carbon monoxide at high altitude
Authors: West J. B.
Published: December 2017

Diffusing capacity of the lung for carbon monoxide (Dl) was measured in London (Pb approx. 750 mm Hg), at 15,300 ft (4,700 m; Pb approx. 440 mm Hg), and at 19,000 ft (5,800 m; Pb approx. 380 mm Hg) on seven members of the Himalayan Scientific and Mountaineering Expedition, 1960–61. At each altitude Dl was measured at two work levels (300 and 900 kg-m/min) and at three different inspired oxygen tensions in order to separate membrane and blood components of the diffusing barrier. A steady state method was used with mixed expired gas analysis; dead space-to-tidal volume ratio was assumed but calculated Dl was insensitive to this. There was no consistent change in Dl at 15,300 ft (subjects breathing ambient air) compared with sea level, but Dl was significantly increased after 7–10 weeks at 19,000 ft (mean changes of 15 and 19% for work levels of 300 and 900 kg-m/min, respectively). However, this small change in Dl can be wholly accounted for by the increased rate of reaction of carbon monoxide with hemoglobin due to hypoxia and by the increased blood hemoglobin concentration.

Submitted on September 7, 1961
Ventricular asynchronism in the dog
Authors: Samet Philip , Bernstein William H. , Litwak Robert S.
Published: December 2017

Dissociation of electrical and mechanical asynchronism in the canine right and left ventricles has been studied by simultaneous registration of right and left ventricular pressure and strain gauge arch curves and the electrocardiogram. Observations were made during sinus rhythm and during acetylstrophanthidin-induced ventricular premature beats with widened aberrant QRS complexes. The data demonstrate only limited mechanical asynchronism during the asynchronous electrical depolarization of ventricular premature systoles.

Submitted on October 19, 1961
Evaluation of slope method for measuring pulmonary blood volume in man
Authors: McGuire Lockhart B. , Dock Donald S. , Hyland John W. , Harrison Donald C. , Haynes Florence W. , Dexter Lewis
Published: December 2017

Knowledge of the pulmonary blood volume is important in several areas of circulatory physiology. However, adequate methods for measuring this volume have not been established. The slope of an indicator-dilution curve across the central circulation has been used in several studies as an indication of this volume. In the present study the blood volume between pulmonary artery and left atrium was measured in 31 human subjects by an application of the well-established mean transit time principle. Slope volumes were also measured. There was poor agreement between the results of the two techniques. Unilateral pulmonary artery occlusion consistently reduced pulmonary blood volume by the mean transit time method, with only minor and less consistent changes in slope volumes. A close correlation between the slopes of curves from simultaneous pulmonary artery and left atrial injections suggested a predominant effect on both curves of factors at or distal to the left side of the heart. It was concluded that the slope method did not measure the pulmonary blood volume in man.

Submitted on June 8, 1961
Effect of acetazolamide on secretion of sodium and potassium by the human stomach
Authors: Lindner A. E. , Cohen N. , Dreiling D. A. , Janowitz H. D.
Published: December 2017

The effect of intravenous infusion of the carbonic anhydrase inhibitor, acetazolamide (Diamox), on the secretion of sodium and potassium by the unstimulated (basal) and histamine-stimulated stomach has been studied in 20 human subjects, using a dosage of 50–100 mg/kg of the drug. Acetazolamide causes a decrease in output of Na and K ions, as well as a decrease in the output of HCI. These effects are more marked after histamine. The reduction in output of K is directly correlated with the reduction in volume rate; however, the decrease in Na output is less than can be accounted for by flow rates. The familiar inverse relationship between concentrations of sodium and hydrogen ions persists after acetazolamide. The effects of actazolamide on secretion of Na and K are believed to follow changes induced by the compound on the primary mechanism of acid secretion.

Submitted on October 30, 1961
Diuresis associated with prolonged water immersion
Authors: Graveline Duane E. , Jackson Margaret M.
Published: December 2017

Utilizing complete water immersion, compensated respiration, and unrestricted activity, the diuretic response of five human subjects to 6-hr periods in this environment was studied. The results indicate that the low specific gravity diuresis which occurs in this situation has characteristics of both a water and an osmotic diuresis. Possible physiologic mechanisms are discussed.

Submitted on September 13, 1961
In vivo studies with an intravascular and intracardiac reflection oximeter
Authors: Enson Y. , Briscoe W. A. , Polanyi M. L. , Cournand A.
Published: December 2017

An oximeter is described which employs two bundles of flexible glass fibers to conduct appropriately filtered light into, and that light diffusely reflected by the blood out of, the blood stream for the determination of oxygen saturation or dye concentration within blood flowing past the tip of either an arterial needle or a cardiac catheter which contains both bundles. The ratio of intensities of the reflected light at two wavelengths is linearly related to oxygen saturation (IRR805/ IRR660) and dye concentration (IRR900/IRR805). Data is reported in vivo and in vitro with respect to accuracy of the determinations (± 1.9%). The effect of patient-to-patient variation in hematocrit and other factors, and of pulsatile blood flow, is described. Application of the technique to physiologic study is illustrated, and theoretical aspects of reflection oximetry, as they apply to the instrument, are discussed.

Submitted on November 17, 1961
Measurement of pulmonary blood flow during exercise using nitrous oxide
Authors: Becklake Margaret R. , Varvis C. J. , Pengelly L. D. , Kenning S. , McGregor M. , Bates D. V.
Published: December 2017

Pulmonary capillary blood flow (Qc) in the exercising subject was calculated from the rate of disappearance of N2O during steady state breathing of an N2O-He-O2 mixture. Measurements were made after alveolar rinsing (reciprocal of N2 washout) had occurred, and up to 30 sec, a time period accompanied by minimal recirculation, since FaNN2O during this period did not rise significantly. Repeatability of the method, judged as the difference of a second estimate from a first on the same subject, was comparable to that reported for the direct Fick technique in resting subjects (31 of 33 paired observations agreed within 20%). Results over a wide range agreed with almost simultaneous measurements by a dye dilution technique (24 of 26 paired observations agreed within 20%), and when related to pulse rate and to Vo2, were comparable to those of the other workers whose subjects were studied in a similar posture. Indeed, this technique (using the indirect Fick principle under “steady state” conditions) probably attains its greatest accuracy during exercise when other methods become less easily applicable.

Submitted on December 18, 1961
Effects of salicylates on exercise metabolism
Authors: Downey John A. , Darling Robert C.
Published: December 2017

Some metabolic effects of salicylates were measured on ten normal young males steadily performing controlled moderate exercise after administration of acetyl salicylic acid (ASA). Dosages at a rate up to 4.8 g/day were administered over lengthening periods, the last dose 1frac12–2 hr before walking on a power-driven treadmill in a temperature-controlled room. Oxygen consumption was measured, as were pulmonary ventilation, pulse rate, and blood lactic acid. While analysis of results indicated increase in resting O2 consumption within 2 hr of the first dose, no modification of O2 consumption of exercise appeared. Pulmonary ventilation was not increased after one dose, but did increase at rest, during exercise, and recovery after longer dosage; O2 extraction from each unit of ventilation increased after one dose at rest and during exercise; the extraction ratio was still increased at rest after longer administration of ASA, but decreased during exercise and recovery. Increased ventilation was predominantly effected by increased depth of respiration rather than by changes in rate. Pulse rates were not changed and no significant effects on the cardiovascular system were discerned in this respect.

Submitted on March 10, 1962