bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of some drugs on reflex vasodilatation of hand produced by radiant heating of trunk
Authors: Appenzeller Otto , Schnieden Harold
Published: December 2017

The effect of some drugs on reflex vasodilatation in the hand was studied. Bretylium tosylate and phenoxybenzamine abolished the reflex vasodilator response in the hand caused by cradle heating of the chest. Alpha methyl dopa, nethalide, and atropine had no effect on this response. It is suggested that the tonic constriction of hand vessels maintained by sympathetic fibers and alpha adrenergic constrictor receptors is temporarily interrupted by 40 sec cradle heating of the chest and that this produces the observed increase in hand blood flow. The reflex increase in hand blood flow with short cradle heating of the chest appears to utilize a common efferent pathway with the vasodilator response produced in the hand by prolonged heating of the legs. On the afferent side, however, these reflexes use different mechanisms.

afferent and efferent pathways; alpha methyl dopa; nethalide; atropine; receptors on hand vessels; bretylium tosylate; phenoxybenzamine

Submitted on February 24, 1964
Lactate and pyruvate gradients between red blood cells and plasma during acute asphyxia
Authors: Daniel Salha S. , Morishima Hisayo O. , James L. Stanley , Adamsons Karlis
Published: December 2017

The rate of equilibration of lactate and pyruvate between plasma and red cells has been studied during asphyxia and following addition of sodium lactate in vivo and in vitro. In the resting, well-oxygenated guinea pig, the mean plasma/red cell ratio of lactate was 1.55 and that of pyruvate 2.47. During asphyxia, the plasma/red cell ratio of lactate rose and that of pyruvate fell, indicating a delay in equilibration. Incomplete equilibration affected particularly the lactate/pyruvate ratio in the two compartments. Infused neutral sodium lactate penetrated the red cells at a rate comparable to that observed following endogenous release of lactic acid during acute asphyxia. In vitro at pH 6.8@#X2013;7.4 at 38 C, the time to 50% equilibration of lactate between plasma and cells of human blood was less than 2 min. It is concluded that during acute asphyxia and resuscitation whole blood values of lactate and pyruvate do not bear a constant relationship to those of plasma.

lactate/pyruvate ratio

Submitted on March 16, 1964
Inert gas-exchange theory using an electric analogue
Authors: Mapleson W. W.
Published: December 2017

When an inert gas of moderate or high solubility in blood is inhaled, the rate at which the alveolar concentration rises toward the inspired concentration increases as the inspired concentration is increased. The only previous systematic analysis of whole-body uptake of inert gases to allow for this effect was restricted to a single, artificial, respiratory pattern and the numerical calculations had to be made on a digital computer. This paper develops the theory for a range of respiratory patterns and shows how the computations may be made on a slightly modified form of a simple electric analogue. It is shown that the rate of saturation of the body increases less markedly with inspired concentration if the inspired alveolar ventilation, rather than the expired alveolar ventilation, is kept constant during the saturation process. Conversely, washout is more rapid with a constant inspired ventilation than with a constant expired ventilation. The theory is extended to show how the uptake of one inert gas may substantially affect the uptake of another, administered simultaneously.

uptake, distribution and elimination; induction; recovery; drugs; inhaled anesthetics; nitrous oxide; diethyl ether; halothane; computers; ventilation; concentration effect; alveolar ventilation

Submitted on February 13, 1964
Pulmonary diffusing capacity and capillary blood volume in normal and anemic dogs
Authors: Jouasset-Strieder Denise , Cahill John M. , Byrne John J. , Gaensler Edward A.
Published: December 2017

The CO diffusing capacity (Dl) was measured by the single-breath method in eight anesthetized dogs. Pulmonary capillary blood volume (Vc) and membrane diffusing capacity (Dm) were determined in six animals by the method of Roughton and Forster. The studies were repeated after anemia had been induced by replacing whole blood with plasma. Large dogs were selected with a mean body weight of 29 kg and a mean alveolar volume of 2,020 ml (STPD) during tests. The mean arterial blood Hb decreased from 14.3 to 6.6 g/100 ml, the mean Dl from 27 to 12 ml/min mm Hg, and the mean Dm from 100 to 47 ml/min mm Hg. Vc averaged 67 ml in the control state and was not significantly changed during anemia. Reductions in Dl and Dm during anemia were proportional to the fall in blood Hb. Both Dl and Dm in all dogs, normal and anemic, were proportional to the volume of red blood cells in the lung capillaries (Vrbc). These results suggest that Vrbc might be an estimate of the useful area of the alveolar-capillary membrane while Dm/Vrbc should vary with changes in its thickness. The latter was not altered by anemia.

alveolar capillary membrane; pulmonary membrane; diffusing capacity; pulmonary capillary RBC volume; pulmonary diffusion pathway; carbon monoxide

Submitted on March 2, 1964
Mechanism of bronchoconstriction during inhalation of sulfur dioxide
Authors: Nadel J. A. , Salem H. , Tamplin B. , Tokiwa Y.
Published: December 2017

Inhalation of SO2 (4–6 ppm) for 10 min decreased airway conductance (increased airway resistance) in seven healthy subjects. Subcutaneous injection of atropine prevented this effect. In anesthetized, paralyzed, artifically ventilated cats, SO2 increased pulmonary resistance, whether delivered to the upper or to the lower airways. This was prevented by complete cold block of the cervical vagosympathetic nerves or by injecting atropine intravenously before the SO2 was inhaled. These results establish the reflex nature of bronchoconstriction during inhalation of SO2.

Note:

With the Technical Assistance of Earl H. White

reflex bronchoconstriction; airway resistance

Submitted on February 18, 1964
Constant-depth halothane anesthesia in respiratory studies
Authors: Brandstater Bernard , Eger Edmond I. , Edelist Gerald
Published: December 2017

Respiratory depression from anesthetic drugs introduces an undefined variable into many experiments. We have produced constant-depth anesthesia in dogs by maintaining an unvarying alveolar concentration of halothane, and we have tested whether such anesthesia can produce a steady state with respect to the respiratory response to CO2. At a constant alveolar halothane concentration, the response to CO2 remained essentially unchanged for up to 8 hr. Carbon dioxide response curves were also obtained at several different alveolar concentrations of halothane. Carbon dioxide response was sensitive to small changes in halothane concentration; the slope of the response curve diminished linearly with increase in alveolar concentration of halothane. With alveolar halothane concentration held constant, a small dose of intravenous thiopental produced a depression of the CO2 response curve that remained for more than 2 hr.

carbon dioxide response; control of respiration; depression; respiratory response

Submitted on April 29, 1964
Postural effect on ventilatory control
Authors: Anthonisen N. R. , Bartlett D. , Tenney S. M.
Published: December 2017

Minute ventilation, alveolar CO2 tension (Paco2), and arterial CO2 tension (Pacoco2) were studied in human subjects during passive tilt from the supine to the erect position. These measurements showed that the erect position was associated with relative alveolar hyperventilation. The hyperventilation of the erect position was found to be almost entirely reversible if hydrostatic effects were removed by water immersion to the level of the xiphoid. Postural changes in ventilation correlated with circulatory changes, suggesting a causal relationship. However, the possibility of a gravity-sensitive abdominal receptor which influences ventilation was not eliminated.

ventilation; alveolar ventilation; posture; alveolar gas tension

Submitted on April 27, 1964
Effect of oxygen upon pulmonary circulation in acclimatized man at high altitude
Authors: Hultgren H. N. , Kelly J. , Miller H.
Published: December 2017

The response to breathing 100% oxygen was studied in 26 acclimatized residents of the Peruvian Andes at altitudes of 12,300 and 14,200 ft. Arterial oxygen saturation increased from 86% to 96%. Mean pulmonary artery pressure decreased by 5 mm Hg and cardiac output did not change. Calculated pulmonary arteriolar resistance was lowered. Pulmonary artery pressure during oxygen breathing was not decreased to normal values observed at sea level. The data suggest the presence of two factors responsible for the increase in pulmonary arteriolar resistance at high altitude: 1) hypoxic vasoconstriction which is reversed by oxygen breathing and 2) anatomic alterations which are not affected by oxygen breathing. Oxygen breathing at high altitude also produced a slowing of the heart rate and increased the relative height of the secondary or tidal wave of the brachial arterial pressure pulse.

pulmonary arteriolar resistance and 100% oxygen; arterial pulse contour–effect of 100% oxygen at high altitude; pulmonary arteriolar resistance–nature of in high altitude; hypoxic vasoconstriction at high altitude–reversal by 100% oxygen breathing; oxygen breathing–comparison of effect on pulmonary circulation at high altitude and sea level

Submitted on May 8, 1964
Controlled frequency breathing during muscular exercise
Authors: Lamb T. W. , Anthonisen N. R. , Tenney S. M.
Published: December 2017

Three human subjects exercised at 2 and 4 mph on a treadmill while breathing room air and 100% oxygen. Respiratory frequency was voluntarily controlled at 6, 12, and 24 breaths/min so that the only ventilatory response possible was a change in tidal volume. Mean CO2 tension of arterialized venous blood was maintained constant near the resting value by each subject under all experimental conditions, including oxygen breathing with the exception of one subject who hyperventilated at 2 mph while breathing 24 times/min. Oscillations in alveolar and arterial Pco2 within each respiratory cycle were markedly altered by respiratory frequency and the intensity of exercise. No relationship was found between Ve, Va, Vt, and the amplitude of oscillation or the rate of change of arterial Pco2 or Po2. Varying levels of the work of breathing were observed while the arterial Pco2 remained constant. It is concluded that the oscillations in arterial Pco2 and Po2 which are observed at rest and during muscular exercise are associated phenomena, not controlling stimuli.

oscillations; chemoreceptors; work of breathing; control of ventilation; frequency of breathing

Submitted on June 17, 1964
Tolerance of hot, wet environments by resting men
Authors: Goldman Ralph F. , Green Edward B. , Iampietro P. F.
Published: December 2017

Studies were conducted on 10-man groups exposed at rest to 51 different hot, wet environmental conditions."Tolerance times" of unacclimatized volunteers established objectively, as the time of occurrence of a rectal temperature of 102.5 F and/or a heart rate of 180 beat/min, were similar to reported values established on a subjective basis. The wet and dry bulb index (WD) of environment was the best predictor of tolerance time. Prior acclimatization to work in hot, dry conditions did not result in prolonged tolerance for resting men exposed to hot, wet environments; neither did it alter the rates of sweat production, the final skin temperatures, or the rates of increase in heart rate or rectal temperature during these resting, hot, wet environmental exposures. Finally, "passive" resting in hot, wet environments (up to 3 hr/day) did not prolong tolerance times or induce other manifestations of heat acclimatization during subsequent resting exposures to hot, wet environments for either unacclimatized or prior, hot, dry, acclimatized subjects.

heat tolerance; acclimatization; sweat rates; heart rates; body temperatures; environmental indices

Submitted on June 17, 1964
Cutaneous circulation during dehydration and heat stress
Authors: Senay Leo C. , Christensen Margaret L.
Published: December 2017

Resting subjects were exposed for 12 hr to 43 C dry bulb, 28 C wet bulb, with and without rehydration. During dehydration, average weighted cutaneous opacity pulse amplitudes decreased 19.5%. An apparent relationship between calculated stroke volume and cutaneous pulse amplitudes existed. A 26% increase in heart rate offset decreases in perfusion per beat and probably contributed to a rise in diastolic pressure. Increases in skin temperature paralleled those of oral temperatures. In most subjects evaporative rates were slightly lower during dehydration. Certain dehydrating subjects maintained sweat rates at control levels but this did not prevent an increase in both oral and skin temperatures. Failure of temperature regulation in these experiments does not appear to be due to a decrease in heat transport or evaporation but rather to a lack of responsiveness of the sudomotor and vasomotor systems to increases in body temperature. Reasons for the temperature rise appear complex.

evaporative weight loss; heat transport; skin temperature; temperature regulation

Submitted on July 22, 1964
Speed of action of atropine on sweating
Authors: Craig F. N. , Cummings E. G.
Published: December 2017

The influence of intravenously injected atropine sulfate on sweating was measured in three men by continuous recording of body weight. Most of the skin surface was kept dry by air movement at 1.5 m/sec. The sequence of events was: completion of injection in 1.1 min; cardiac acceleration in 1.3 min; and inhibition of sweating in 3.5 min. The minimum rate of weight loss occurred at a dose of 0.5 mg; larger doses prolonged the inhibition without intensifying it. Heat storage was equal to an average of 92% of the deficit in evaporative heat loss. Although sweating returned to the initial rate within an hour, the normal increase in sweating at elevated body temperatures was prevented for the next hour. Sweating responds to atropine almost as rapidly as the cardiac rate. The degree of inhibition is independent of the initial rate of sweating.

heart rate; skin temperature; rectal temperature; heat exposure; heat loss by evaporation; man continuous recording of body weight; exercise

Submitted on June 24, 1964
Oxyhemoglobin dissociation curve in liver disease
Authors: Caldwell P. R. B. , Fritts H. W. , Cournand A.
Published: December 2017

The in vivo oxyhemoglobin dissociation curves of patients with liver disease appear to be displaced to the right of those of normal men. Although the displacement is small it may contribute to the arterial unsaturation which sometimes occurs.

hemoglobin; oxygen electrode; unsaturation

Submitted on March 9, 1964
A hyperbaric chamber for small animals
Authors: Van Tassel Peter V.
Published: December 2017

A portable chamber, 30 liters in capacity, for the exposure of small animals to hyperbaric atmospheres is described. It can be used with pressures up to 7.5 atm, has walls of transparent plastic which allow almost unlimited visibility of the interior, and can be built at relatively low cost. Construction details and some recommendations for testing and use are given.

high pressure oxygen

Submitted on July 16, 1964
Effects of external elastic and threshold loading on breathing in man
Authors: Freedman S. , Weinstein Stephen A.
Published: December 2017

Conscious human subjects, seated in a soundproof chamber, were made at intervals to inspire through external elastic or threshold loads for from 4 to 15 breaths With threshold loading of -5 to -15 cm H2O (13 subjects) initially, the first loaded breath was smaller than preceding breaths with tidal volume returning to normal within 6 breaths. With further presentations, tidal volume returned to control values sooner. After six presentations, 10 subjects had no diminution in tidal volume on the first loaded breath. With elastic loading, of 10 cm H2O/liter (five subjects) and 19.5 cm H2O/liter (four subjects) a different type of adaptation occurred. This was characterized by decreased tidal volume and increased frequency. With the larger load, after three presentations frequency was increased during loaded breathing, due to a conscious effort by the subjects. The results show that repeated presentation of an elastic or threshold load leads to a change in the response to the load in a manner analogous to the learning of voluntary motor acts.

respiration; learning; tidal volume; respiratory frequency; regulation of respiration

Submitted on July 9, 1964
Tracheal motion during eupnea
Authors: Scarpelli Emile M. , Real Franz J. P. , Rudolph Abraham M.
Published: December 2017

A method is described for the direct measurement of upper airway circumference and length with mercury strain gauges fixed to the trachea and main bronchus. The gauges were permanently placed in dogs and were used in serial studies in the intact animal, anesthetized and unanesthetized. The method proved to be reliable and relatively unaffected by extraneous factors. Three types of tracheal motion were observed during eupnea: 1) Primarily passive changes in tracheal length and circumference during each respiratory cycle; the circumference changes could be related to changes in transmural pressure and the length changes related to the over-all downward movement of the lungs during inhalation. 2) The breath-by-breath tracheal motion was superimposed on rhythmic alterations of length and circumference mediated through the vagus nerves. 3) There was a tonic tracheoconstriction which was also dependent on vagal innervation. All changes in airway dimensions involved the entire trachea as a unit, with no evidence for tracheal peristalsis. Changes in airway volume were calculated from the length-circumference data.

Note:

(With the Technical Assistance of Bernard Minter)

direct measurement of airway dimensions; mercury strain gauge; vagal innervation and tracheal dimensions; tracheal volume

Submitted on July 13, 1964
Lung function and blood-gas exchange, before and after cardiac surgery
Authors: Weintraub H. D. , Sullivan S. F. , Malm J. R. , Bowman F. O. , Papper E. M.
Published: December 2017

Lung volumes, bellows functions, and lung blood-gas distribution have been studied in 15 patients with severe acquired valvular heart disease. Nine of these patients were also studied after definitive surgical correction. Vital capacity which was decreased an average of 26% did not change postoperatively. Functional residual capacity, residual volume, and total lung capacity did not change significantly. Maximal voluntary ventilation and forced expiratory volume (1 sec) did not change significantly. No abnormality was detected in the intrapulmonary mixing of inspired gas either before or after operation. Mean arterial oxygen tension was 10–15 mm Hg lower than normal. The mean shunt fraction of total cardiac output was 3.1% and increased insignificantly to 4.1% postoperatively. The alveolar-arterial oxygen tension difference ((A – a)DO2) was high. However, no change was noted after operation. The nonshunt component of the (A – a)DO2 was higher than normal and did not change after operation.

alveolar-arterial oxygen tension differences; lung function in acquired valvular heart disease; shunts; lung blood-gas distribution

Submitted on June 29, 1964
Pulmonary vasoconstriction during histotoxic hypoxia
Authors: Lloyd Thomas C.
Published: December 2017

Increases in pulmonary vascular resistance could be produced in excised perfused ventilated dog lung lobes by lowering the alveolar Po2. When dinitrophenol was added to the perfusate a similar change in the vascular bed occurred that could be reversed by ventilating with supernormal oxygen concentrations. The similarity of the responses to dinitrophenol and lowered alveolar Po2 was demonstrated using normally and retrogradely perfused lobes. The hypoxic pressor response was shown to be independent of the Po2 of blood contained in the arteries and veins.

Note:

(With the Technical Assistance of Emily McCartney)

dinitrophenol; cyanide; vascular effect of intravascular oxygen concentration

Submitted on August 13, 1964
Critical studies on determination of thyroid secretion rate in cold-adapted animals
Authors: Héroux O. , Brauer R.
Published: December 2017

Estimation of thyroid secretion rate by determining the amount of l-thyroxine required to block the thyroidal I131 release, confirmed that the thyroxine requirement of 6 C-acclimated rats is twice as high as that of 23 C-acclimated controls (5.5 ± 0.7 μg/100 g per day against 2.73 ± 0.3 μg/100 g per day). In white rats acclimatized to cold by outdoor exposure during the winter on the other hand, it was only 1.8 ± 0.38 μg/100 g per day. Larger amounts of thyroxine were found in the feces of the 6 C-acclimated rats (1.66 ± 0.66 μg/100 g body wt per day) as compared to 0.69 ± 0.07 μg/100 g body wt per day for controls. Urinary elimination rates of I131 were more rapid in “6 C rats” than in controls. These observations indicate that the greater requirement for thyroxine in cold-adapted rats is at least partly due to greater fecal loss of the hormone. It seems plausible to seek an explanation for the lesser thyroxine requirement of the outdoor winter rats in their fecal elimination rate of that hormone.

cold acclimation; fecal excretion of thyroxine

Submitted on June 18, 1964
Alterations in pulmonary mechanics with airway obstruction during rest and exercise
Authors: Hanson John S. , Tabakin Burton S. , Levy Arthur M. , Falsetti Herman L.
Published: December 2017

The effects of artificial expiratory airway obstruction on pulmonary compliance, work of breathing, and pressure-flow relationships have been studied in five normal young males at rest and during treadmill exercise. The finding of a significant decrease in compliance during resistance breathing strongly suggests that alterations in pulmonary blood volume have occurred. In addition, there is evidence that uniformity of gas distribution within the lung has been impaired, a finding which is consonant with previously studied changes in lung volumes secondary to the obstruction.

expiratory airway obstruction; compliance; work of breathing; pulmonary mechanics during exercise; resistance breathing during exercise

Submitted on October 8, 1964
Measurement of the cutaneous circulation
Authors: Wright Harry M.
Published: December 2017

Relationships between four commonly used indirect methods for study of the cutaneous circulation in intact, unanesthetized man were examined. Skin temperature, thermal conductance, volume plethysmography and the light absorption of the skin (as related to hemoglobin content) were simultaneously recorded on the upper extremities of normal young men as blood flow and blood content of the skin were changed by circulatory arrest, venous occlusion, indirect heating and cooling, and changes in position. Skin temperature and thermal conductance changed along parallel courses as blood flow was changed, while finger volume and reflectance of the skin to light of wavelength 550 mμ both changed in expected directions although along different courses, following passive congestion and de-congestion and changes in level of the hand relative to the heart. The advantages, disadvantages, and limitations of each of the methods in the study of cutaneous circulation in man are discussed and compared.

measurement of circulation of skin; methods for measurement of cutaneous circulation; blood flow through skin; blood content of skin; skin

Submitted on March 12, 1964
Comparison of CO2 rebreathing and acetylene methods for cardiac output
Authors: Klausen K.
Published: December 2017

The cardiac output during rest and work was determined by a CO2 rebreathing method as suggested by Defares. The partial pressure of CO2 in the mixed venous blood (PvCOCO2) was calculated from the rise of the CO2 percent in a Grollman bag during rebreathing. In the rest experiments the partial pressure of CO2 in arterial blood (PaCOCO2) was obtained from analysis of alveolar samples taken by the Haldane-Priestley direct sampling method. In the work experiments the PaCOCO2 was calculated using the Bohr formula and a dead space estimated from Asmussen and Nielsen's data. The metabolic rate including both O2 uptake and CO2 output was determined by the Douglas bag method. In each experiment the acetylene method as described by Christensen was applied after the CO2 rebreathing method. The values obtained by the two methods were almost identical, the standard deviation for all experiments being ±7.3%, and were of the same magnitude as those obtained by others with the dye-dilution or direct Fick method both during rest and work.

cardiac output at rest and work; arterial Pco2 and venous Pco2 at rest and work; stroke volume at rest and work

Submitted on November 25, 1964
A large environmental chamber for the study of hypercapnia and hypoxia
Authors: Schwartz William B. , Silverman Leslie
Published: December 2017

The design and operating characteristics of an environmental chamber which can maintain carbon dioxide concentrations between 1 and 20% and oxygen concentrations between 5 and 21% are described. The chamber, which measures 3.66 x 6.10 m (12 x 20 ft), permits acute and chronic studies to be carried out in either large animals or man. Multiple safety features serve to protect the occupants against failure of equipment or controls. The relative ease with which investigators can work in the chamber, the convenience of long-term operation, and the reliability of the system which controls the gas concentrations provide a unit which has proved useful for the investigation of a variety of physiologic phenomena related to hypercapnia. Preliminary observations indicate that acute and chronic studies of hypoxia will be equally feasible.

acid-base; anoxia; respiratory acidosis

Submitted on May 11, 1964
Nomogram for temperature correction or electrode calibration during Po2 measurements
Authors: Hedley-Whyte J. , Radford E. P. , Laver M. B.
Published: December 2017

A nomogram has been constructed based on temperature correction factors needed when the O2 tension of an aqueous solution is measured after warming or cooling the solution in a sealed container. Since blood has a constant solubility relative to water at O2 tensions above 200 torr, this nomogram is suitable for use when measuring the O2 tensions of fully saturated blood. This nomogram may also be applied to calibrate an O2 electrode by a technique which avoids the need for special calibrating gases.

relative solubility; O2 electrode; hypothermia; tonometry; Bunsen coefficients; hyperbaric oxygenation

Submitted on October 12, 1964
Neutrophilic granulocyte kinetics in normal man
Authors: Alexanian Raymond , Donohue Dennis M.
Published: December 2017

A method has been described for the labeling, separation, and estimation of radioactivity in samples of DFP32-tagged neutrophilic granulocytes. Studies were performed to identify the potential errors of this procedure, and it was then applied to a group of 12 normal men. A mean of 43% of transfused, labeled neutrophilic granulocytes was found in the circulation, resulting in the calculation of a mean maximum of 0.68 x 109/kg neutrophilic granulocytes in the total peripheral vascular pool. The mean half-time of disappearance of these cells was 3.8 hr, and a mean maximum neutrophile turnover rate through peripheral blood of 3.2 x 109/kg per day was calculated. The failure of labeled cells to disappear from the blood at an exponential rate suggested that the instantaneously equilibrating blood neutrophile pools may be in slower equilibrium with a larger, extravascular neutrophile compartment.

Note:

(With the Technical Assistance of Yvonne Betson and Ruth Henderson)

DFP32; liquid scintillation counting of granulocytes; circulating and noncirculating blood neutrophile pools; extravascular neutrophile pool; neutrophilic granulocyte turnover

Submitted on August 31, 1964
Some responses of humans to thermal radiation
Authors: Suggs Charles W.
Published: December 2017

The effects of thermal radiation on heart rate, ventilation rate, and oxygen consumption rate were investigated at various conditions of dry-bulb temperature, air velocity, and exercise. Ventilation rate and oxygen consumption rate were essentially independent of thermal radiation under all the environmental conditions investigated. However, heart rate increased appreciably with increases in thermal radiation provided the environment was already warm or hot. In the range between 70 and 100 F dry bulb, a 7 F increase in mean radiant temperature was found to elicit the same average increase in heart rate as a 1 F increase in dry bulb. For a cool environment the response tended to be reversed with the heart rate decreasing as the environment was made more comfortable by the addition of thermal radiation. Exercise shifted the point at which this reversal occurred toward lower temperatures.

heat stress; heart rate; thermal intensity

Submitted on July 16, 1964
Blood O2 content measurements using the oxygen electrode
Authors: Laver Myron B. , Murphy Anna J. , Seifen Astrid , Radford Edward P.
Published: December 2017

A method is described for determining the oxygen content in whole blood with the membrane-covered oxygen electrode that requires less time and skill than the Van Slyke-Neill technique. A blood sample (0.05 ml) is mixed with a large volume of dilute (0.2% w/v) potassium ferricyanide solution in equilibrium with ambient air and the oxygen tension of the mixture is measured at a known temperature. The whole-blood oxygen content is obtained by subtracting the calculated O2 content of the ferricyanide solution from that of the blood-ferricyanide mixture. The method is based on the assumption that the Bunsen O2 solubility coefficient of the ferricyanide solution, with or without the added blood sample, is equal to the solubility coefficient of water. Data have been presented to validate this assumption. Whole-blood O2 contents measured simultaneously with the oxygen electrode and the Van Slyke-Neill technique were found to be in close agreement.

flood-gas determination

Submitted on January 11, 1965
Pulsatile flow in rigid tubes
Authors: Linford Robert G. , Ryan Norman W.
Published: December 2017

The purpose of this study was to examine critically the theoretical equations derived for pulsatile laminar flow in rigid straight tubes. These equations, presented in their most useful form by J. R. Womersley in 1955, give the fluid flow rate as a function of the pressure gradient-time relationship, pulse frequency, fluid properties, and tube radius, and they give the fluid velocity as a function of the above quantities and the radial position in the tube. A pulsatile flow apparatus was constructed which would allow measurement of all the variables mentioned above, and a computer program based on Womersley's equations was used to calculate the fluid flow rate and velocity profile from the pressure gradient-time relationship, fluid properties, and tube radius. Thus a comparison between measured and calculated values of flow and velocity could be made. Calculations and data agree within the estimated experimental error, thus providing evidence of the applicability of the theoretical equations to actual flow with large pulse amplitudes. The analog computer “pressure gradient technique” of D. Fry and associates was compared with the exact solution for straight rigid tubes and found to deviate less than 20% in amplitude and phase except at very low frequencies.

hydrodynamics, pulsatile flow; blood flow, arterial; hemodynamics, pulse characteristics

Submitted on April 6, 1964
Effects of changes in topographical distribution of lung blood flow on gas exchange
Authors: West John B. , Jones Norman L.
Published: December 2017

The left lung of a dog was suspended in a Lucite box, ventilated with negative pressure, and perfused with venous blood from another dog at 37 C. By varying the pulmonary artery pressure, it was possible to perfuse all the lung or leave increasing proportions of the upper and middle lobes unperfused. The mean Pco2 difference between end-tidal gas and pulmonary venous blood was 1.7 mm Hg (se mean 0.6) when all the lung was perfused, but steadily increased up to 17 mm Hg as more and more of the lung was unperfused. Alveolar dead space/alveolar tidal volume increased linearly with the proportion of lung unperfused. By contrast, the venous admixture component remained small as increasing amounts of lung were unperfused. The results were compared with calculations made on a theoretical model of the lung and it was concluded that the uneven distribution of blood flow caused by hydrostatic pressure differences down the lung may seriously interfere with CO2 exchange when the pulmonary artery pressure is low, but that this type of uneven distribution affects O2 exchange much less.

isolated lung; hydrostatic effect; alveolar-arterial differences; physiologic dead space; alveolar dead space; shunt effect; venous admixture; increased acceleration; hypoxemia; hemorrhage; positive-pressure breathing

Submitted on September 10, 1964
Effect of CO2 and whole-body vibration on ventilation
Authors: Young W. A. , Shaw D. B. , Navach J. , Shizgal H. , Kowalsky N.
Published: December 2017

The ventilatory response of six subjects to increasing levels of alveolar CO2 was measured at rest and during the hyperventilation induced by passive vibratory movements of the whole body. During vibration, addition of CO2 to the inspired air produced no increase in ventilation until the PaCOCO2 reached a critical level which coincided closely with the intersection of the vibration with the resting CO2 response curve. Above this level the vibration curve was almost superimposed on the resting one. There was no evidence of an additive effect of the two stimuli, and no increase in sensitivity to CO2 during vibration. In these respects the situation differs from that in which CO2 is combined with hypoxia or hyperthermia. The findings indicate that when respiration is stimulated by vibration and CO2 simultaneously, the resultant ventilation at any point is solely that produced by the stronger of the two stimuli.

hyperventilation; PaCOCO2 and ventilation; CO2 response curve and vibration

Submitted on July 30, 1964
Altered surface tension of lung extracts and lung mechanics
Authors: Tierney D. F. , Johnson R. P.
Published: December 2017

Reduction of the surface area of 24 extracts of rabbit lungs by four-fifths decreased the surface tension to a minimum value of 0–5 dynes/cm at 18–22 C. However, minimum surface tension was above 15 dynes/cm if 1) the temperature was raised to 42 C, 2) the extract was prepared with distilled water, 3) phospholipase C was incubated with the extract, and 4) cholesterol or oleic acid was added to the surface. If blood or serum was added during the extraction, minimum surface tension was usually (although not invariably) elevated. Rinsing diluted rat serum or chylomicrons through the airways increases elastic recoil of excised rat lungs. Other reports show that heating a lung above 42 C or rinsing a solution of phospholipase C through the airways also increases elastic recoil of excised rat lungs. Therefore, these conditions alter the surface tension of lung extracts and the pressure-volume characteristics of the lungs concordantly. In addition, we found that the surface tension of lung extracts was not stable below 24 dynes/cm. Similar instability of the surface within the lung should lead to gradual atelectasis if a low transpulmonary pressure is maintained.

elastic recoil; atelectasis; compliance; lung surface

Submitted on January 21, 1965
Critical temperature for instrumental response acquisition in hypothermic rats
Authors: Panuska J. A. , Popovic V. P.
Published: December 2017

Fifty-one previously untrained adult white rats were cooled to colonic temperature of 18.5 C and were rewarmed to various body temperatures between 23 and 31 C. After their body temperature stabilized at a chosen level, rats were placed in a chamber with the possibility of using a lever-activated heat reinforcement apparatus. The temperature of the chamber was 2 C. Each experiment lasted 180 min. During this time the rats either started to press the lever steadily for external heat or at the end of this experiment they became even more hypothermic. In a group of 41 rats kept at a body temperature of 25 C or above, 38 animals used the simple heat reinforcement apparatus and responded effectively, thus rewarming themselves to euthermia. Animals at a higher body temperature acquired the response earlier than animals whose body temperature was lower. When the body temperature was 25 C or below, the rats failed to acquire the response. Thus it appears that body temperature of 25 C is a critical body temperature for this simple response acquisition.

behavioral temperature regulation; body temperature; heat reinforcement; hypothermia; learning; performance

Submitted on April 1, 1965
Body temperatures in some Australian mammals. V. Aboriginals
Authors: Morrison Peter
Published: December 2017

Skin temperatures were measured on nine body areas with a portable radiometer at the beginning and at the end of a night of sleep in early summer. The subjects, young Australian aboriginal men and women from Haast's Bluff, slept in their normal circumstances outside on the ground with little protection. With some cover or on warmer, cloudy nights (average air temperature of 26.5 C), there were no losses in temperature beyond the expected nocturnal decline. With minimal cover on clear, cool nights when temperatures ranged down to 19 C for air and ground and to 4 C for sky, substantial losses were found for the 6-hr period: 33.2–30.4 C for the forehead; 27.7– 20.8 for the feet; 30.5–27.2 for the mean of the exposed skin; and 37.0–35.1 for the mouth. The maintenance of sleep at this level of cooling (minimum foot value = 17.6 C) represents a valuable adaptation in these people. Tropical aboriginals from Mornington and Bentinck Islands did not exhibit this tolerance, and insisted on cover even on warm nights (air temperature of 27 C) which did not depress skin temperature.

cold; skin temperature; adaptation

Submitted on December 21, 1964
Renal clearances during prolonged supine exercise at different loads
Authors: Grimby Gunnar
Published: December 2017

Clearance of inulin (CIn) and para-aminohippuric acid (CPAH), cardiac output, oxygen uptake, and arterial blood pressure were measured in 15 healthy male subjects at rest and during supine exercise of 45 min duration on a bicycle ergometer. Work loads between 150 and 900 kpm/min were chosen. CPAH decreased with increasing work intensity (heart rate). At an oxygen uptake corresponding to half of the aerobic work capacity it was about 70% and at heavy work 35–45% of the value at rest. The renal fraction of the cardiac output averaged, at rest, 17% and decreased with increasing work loads to 2.5–5% as a minimum. CIn did not change significantly until heavy exercise was performed. The filtration fraction increased during exercise.

clearances of inulin and para-aminohippuric acid; cardiac output

Submitted on May 28, 1965
Excess lactate concept and oxygen debt of exercise
Authors: Wasserman Karlman , Burton George G. , Van Kessel Antonius L.
Published: December 2017

The Huckabee concept that “excess lactate” (XL) is equivalent to the O2 debt of exercise and physiological phenomena derived therefrom, were investigated. Measurements of O2 debt, arterial blood lactate and XL, and O2 consumption were made during cycle ergometer exercise of controlled intensity and duration. Our results indicate: 1) The oxygen equivalents of XL as well as Delta lactate are less than the O2 debt, at all work loads. 2) The concentration of XL does not linearly increase during exercise. 3) The anaerobic metabolic rate whether calculated from XL or O2 debt is not a constant fraction of the metabolic rate, at all work loads. A larger fraction of energy is derived from the O2 debt creditors at heavy and very heavy than at moderate work loads. 4) In 30 controlled work-load exercise studies of prolonged duration, XL did not contribute any information not revealed by lactate itself. 5) The differences between Huckabee's results and those of our own are not due to differences in the measurement of XL but rather to differences in the directly measured O2 debt.

anaerobic metabolism; O2 debt creditors; O2 consumption

Submitted on January 4, 1965
A nonthrombogenic diffusion membrane for continuous in vivo measurement of blood gases by mass spectrometry
Authors: Brantigen J. W. , Gott V. L. , Vestal M. L. , Fergusson G. J. , Johnston W. H.
Published: December 2017

A heparinized silicone rubber diffusion membrane covering a 22-gauge stainless steel intravascular cannula allows continuous in vivo measurement of blood gas tensions by mass spectrometry in an unheparinized animal or patient. This system has been tested in the aortas of a series of five dogs for periods up to 24 hr, and nonheparinized controls have been used in two dogs. The controls showed evidence of membrane coagulation, but the heparinized membranes were non-thrombogenic and provided quantitatively accurate measurements of Po2 and Pco2 throughout.

nonthrombogenic materials; blood gas tensions; oxygen; carbon dioxide; monitoring devices

Submitted on July 18, 1969
Effect of preinspiratory lung volume on closing volume determination by nitrogen method
Authors: Kaneko K. , Mohler J. , Balchum O.
Published: December 2017

The effect of preinspiratory lung volume on the N2 closing volume (CV) was studied in simulated CV determination in a lung model. The model analysis supports our hypothesis that inspiration of O2 initiated at the “closing capacity” (CC = CV ;V) will improve the resolution of the inflection point between phases III and IV. It further indicates that if the inflection point is located by extrapolating the terminal portion of phase IV, then the original N2 method could underestimate CV systematically as much as 5% VC because of the relatively small initial rise in N2 concentration. Conversely, the CV obtained by the modified method should be closer to the value obtained by the “bolus method.” In practice, the modification can be done simply by adding a dead space (DS) with its capacity equal to CV (600–700 ml in male adults). The theoretical lung model analysis was confirmed by the experimental study, which showed that CV with DS was consistently larger than CV without DS (a mean difference of 4.7% VC).
Technique for accurately producing desired carboxyhemoglobin levels during rest and exercise
Authors: Dahms T. E. , Horvath S. M. , Gray D. J.
Published: December 2017

A method is described for accurately adjusting a subject's blood carboxyhemoglobin (HbCO) level and then maintaining this level during either rest or exercise. The data presented describe the constancy with which HbCO levels (between 3 and 5% HbCO)were maintained despite varying the inspired ventilatory volumes from 5 to 120 1/min (BTPS). After an initial bolus inhalation of CO to bring the blood HbCO to a desired level, the concentration of CO in the inspired air to maintain this level of HbCO can be predicted from the following equation: COI (ppm) = desired %HbCO divided by 0.180.
Effects of training on the physiological responses to one- and two-leg work
Authors: Davies C. T. , Sargeant A. J.
Published: December 2017

The effects of training resulting from one-leg exercise on a stationary bicycle ergometer have been studied. Seven subjects were habituated to one- and two-leg progressive exercise tests on 11 successive days and were then trained for 60 min-day-1 (30 min each leg) 3 times per wk for 5–6 wk at approximately 80% of their one-leg VO2 max. VE max increased (P less than 0.05) by approximately 14 1-min-1 and VO2 max by approximately 0.34 1-min-1 (+14%; P less than 0.05) in one-leg exercise. This latter increase was not, however, reflected in the two-leg VO2 max which only increased 145 ml-min-1 (4.7%). It was concluded that training is specific and in one-leg work the phenomenon is mainly peripheral in origin, but in two-leg work the limitation to maximal exercise is still provided by the capacity of the central cardiovascular system to transport oxygen to a given effective muscle mass.
An exchangable intra-atrial balloon device
Authors: Chapman L. W. , Mittmann U. M.
Published: December 2017

An exchangeable atrial balloon device is described. It consists of an outer guide and a latex Foley urinary retention catheter. The guide is sutured into the atrial appendage and brought out through the chest wall. The advantages of the device are discussed.
Mitochondrial enzymatic adaptation of skeletal muscle to endurance training
Authors: Benzi G. , Panceri P. , de Bernardi M. , Villa R. , Arcelli E. , D'Angelo L. , Arrigoni E. , Berte F.
Published: December 2017

Some mitochondrial enzymatic activities (succinate dehydrogenase, NADH cytochrome reductase, cytochrome oxidase) were studied in the gastrocnemius and soleus muscle of the rat. The modifications of the enzyme activity, induced by endurance training, were found to be functions of 1) daily work load and 2) total training time. The treatment with an effective dose of vasodilating substances (papaverine, nicergoline, dipyridamole, and bamethan) showed that 1) nicergoline, bamethan, and dipyridamole were differently able to shorten the time of appearance of the increase in the enzymatic activities; 2) however, long-term treatments with these drugs did not prove able to modify the plateau level of the enzymatic activity increase, for a given amount of endurance training; 3) the pharmacodynamic effect on enzymatic activities was in no way related to the vasodilating effect of these drugs, since the effect was not observed with papaverine. The transition from a given level of endurance training to a lower one led to a proportional decrease of the mitochondrial enzymatic activities, thus pointing out the relation between amount of training and enzymatic activity. The drugs studied were unable to modify the decrease of enzymatic activity induced by lower work load.
Constant-load versus heart rate-targeted exercise: responses of systolic intervals
Authors: Lance V. Q. , Spodick D. H.
Published: December 2017

Eight normal male volunteers were studied during bicycle ergometry at constant work loads of 50, 100, and 150 W for 4 min each and heart rate-targeted exercise to rates which matched those during the end of the 4th min at each constant work load. Systolic intervals measured prior to and during exercise included: Q-IM, isovolumic contraction time (IVCT), preejection period (PEP), left ventricular ejection time (LVET), ejection time index (ETI), PEP/LVET, and pulse transmission time (PTT). Directional changes during both exercise methods were consistent with previously reported results. Comparable control values indicated equivalent starting points for each bout and confirmed recovery from preceding exercise. There was striking similarities within each matched exercise set for Q-IM, IVCT, PEP, and PEP/LVET. LVET was significantly shorter for rate targeted exercise. We conclude that either constant-load or rate-targeted bicycle ergometry may be employed with choice of method determined by the purpose of the protocol and that systoloc intervals (except LVET) should not be importantly altered owing to the method chosen.
Deep body temperature from aural canal with servo-controlled heating to outer ear
Authors: Keatinge W. R. , Sloan R. E.
Published: December 2017

A portable battery-powered device was used to measure temperature in the external aural canal by a thermistor while keeping the temperature of the outer ear, monitored by a second thermistor at the same level by servo-controlled heating. Aural canal temperature then always stabilized within 0.35 degrees C of esophageal in moving air at between 18 and 45 degrees C. It often did so in colder air, but stabilization was slow even after brief exposure to the cold air. Aural temperature then paralleled esophageal within 0.35 degrees C during rapid changes in deep body temperature while rectal temperature was seriously depressed in cold air. These conclusions were based on 30 experiments on 11 male and 7 female subjects.