bluuebunny/crossref_metadata_2025 huggingface dataset:
Human auditory system response to modulated electromagnetic energy
Authors: Frey Allan H.
Published: December 2017

The intent of this paper is to bring a new phenomenon to the attention of physiologists. Using extremely low average power densities of electromagnetic energy, the perception of sounds was induced in normal and deaf humans. The effect was induced several hundred feet from the antenna the instant the transmitter was turned on, and is a function of carrier frequency and modulation. Attempts were made to match the sounds induced by electromagnetic energy and acoustic energy. The closest match occurred when the acoustic amplifier was driven by the rf transmitter's modulator. Peak power density is a critical factor and, with acoustic noise of approximately 80 db, a peak power density of approximately 275 mw/ cm2 is needed to induce the perception at carrier frequencies of 425 mc and 1,310 mc. The average power density can be at least as low as 400 μw/cm2. The evidence for the various possible sites of the electromagnetic energy sensor are discussed and locations peripheral to the cochlea are ruled out.
Myocardial energy substances in the dog heart during potassium and hypothermic arrest
Authors: Gott Vincent L. , Bartlett Marilyn , Long David M. , Lillehei C. Walton , Johnson John A.
Published: December 2017

Canine hearts were arrested with potassium citrate at 37 C and with cold blood at 17 C. Biopsies were taken from the nonperfused hearts at 0, 5, 20, and 60 min and analyzed by specific microtechniques for AMP, ADP, ATP, phosphocreatine, inorganic phosphate, glycogen, lactic acid, and pyruvic acid. During potassium citrate arrest at 37 C the ATP level was reduced 4.41 mmoles/kg to an average value of .77 mmoles/kg. During hypothermic arrest the ATP level decreased only 1.88 mmoles/ kg. Arrested hearts at 37 C utilized four times as much glycogen and produced three times as much lactic acid as hearts at 17 C. Phosphocreatine fell to low values in both types of arrest within 20 min. The levels of AMP, ADP, and pyruvic acid remained fairly constant throughout the period of arrest. It appears from this data and earlier human biopsy data that selective hypothermic arrest is tolerated far better than potassium citrate arrest.

Submitted on September 18, 1961
Relative importance of various tissues in joint stiffness
Authors: Johns Richard J. , Wright Verna
Published: December 2017

The rheological properties of the cat”s wrist were found to be similar to those of the human metacarpophalangeal joint. In the intact joint nonlinear elasticity and plasticity accounted for most of the stiffness, elasticity being twice as great as plasticity. Inertia accounted for <6% of the total torque, and viscosity <2%. Frictional torques were immeasurably small, being <0.1% of the total. The joint capsule contributed 47%, passive motion of the muscles 41%, the tendons 10%, and the skin 2% to the total torque required to move the joint in its midrange. Toward the extremes of joint motion the restraining effect of tendons became more important.

Submitted on February 8, 1962
Tissue pO2 and pCO2 estimation with rat subcutaneous gas pockets
Authors: Van Liew Hugh D.
Published: December 2017

This study appraises use of gas pockets for estimation of tissue pO2 and pCO2. a) Tensions of O2 and CO2 in rat subcutaneous pockets in the constant composition state were compared with tissue tensions estimated by a special interpolation technique using the pockets; the two types of results were not appreciably different. b) Possible values for venous blood pO2 and pCO2 were estimated by a “blood r” curve; agreement between expected blood tensions and gas pocket tensions supports the hypothesis that pockets closely reflect a tissue region's venous blood. c) Initial composition adjustments after introduction of five different mixtures of O2, CO2, and N2 into the pockets were studied; the results were used to illustrate some theoretical properties of gas pockets in the body.

Submitted on April 23, 1962
Phenylalanine metabolism in control subjects, mental patients, and phenylketonurics
Authors: Sacks William
Published: December 2017

After injection of dl-phenylalanine-1-C14 or l-phenylalanine-1-C14, C14O2 specific activities in whole blood were frac15–frac13 as high as those after injection of dl-tyrosine-1-C14 or l-tyrosine-1-C14 in normal subjects and chronic psychotic patients. In phenylalanine-C14 studies, tyrosine specific activities were 1/16–1/10 of corresponding phenylalanine specific activities. After injection of l-phenylalanine-1-C14 into two phenylketonuric (PKU) patients, C14O2 activities in one, a child, approximated those in other experiments, whereas they were lower in the adult PKU-patient. Maximal tyrosine specific activity (adult PKU patient) was frac16 the corresponding phenylalanine specific activity. Ratios of specific activities of maximal C14O2 to phenylalanine were similar in the control subject and PKU patient, suggesting that catabolism of phenylalanine proceeds at the same rate in phenylketonuria. Results with l-phenylalanine-U-C14 indicated that more than the carboxyl carbon contributed to blood 14O2. The data suggest that hydroxylation of phenylalanine to form tyrosine may be a minor pathway in intermediary metabolism of phenylalanine in normal humans and in chronic psychotic and phenylketonuric patients.

Submitted on April 11, 1962
External work in walking
Authors: Cavagna G. A. , Saibene F. P. , Margaria R.
Published: December 2017

From records obtained from a triple accelerometer applied to the trunk of a subject the displacements of the trunk in vertical, forward, and lateral directions have been calculated. With motion pictures taken simultaneously, displacements of the center of gravity within the body were measured. From these data the external mechanical work of walking was calculated. The sum of work for vertical and for forward displacements of the center of gravity of the body gives the total external work; energy for the lateral displacements was negligible. Total external work appears to be lower than that calculated from the vertical displacements alone, because work done in lifting is partly sustained by the inertial force of the forward-moving body. Total external work reaches a highest value (0.1 kcal/km kg) at the most economical speed of walking, 4 km/hr, which corresponds to an energy consumption of 0.48 kcal/km kg. At this speed the internal work appears negligible; it amounts to appreciable entities at very low speeds because of the static contractions of the muscles, and at high speeds because of considerable stiffening of the limbs and movements not involving a displacement of the center of gravity.

Submitted on May 25, 1962
Hydraulic input impedance to aorta and pulmonary artery in dogs
Authors: Patel Dali J. , deFreitas Flavio M. , Fry Donald L.
Published: December 2017

Pressure-flow relationships were studied at the root of the aorta and the pulmonary artery in 18 dogs. The hydraulic input impedance to the vascular bed was calculated as a complex ratio of the corresponding pressure and flow harmonics. Results indicate: a) The predominant features of the load against which the heart is pumping consists of an impedance with a magnitude that initially decreases rapidly with frequency and then increases gradually with frequency. In general, pressure tends to lag behind flow for all harmonics. b) The input impedance versus frequency patterns provided a logical basis for choosing various simple electrical networks which can be used to characterize in a compact manner the general features of the hydraulic load presented to the ventricles. c) The hazards of using such simple networks to define the physical properties of the vascular system are pointed out.

Submitted on July 5, 1962

Submitted on July 30, 1962
Temperature-humidity effects on thyroxin I131 disappearance rates in cattle
Authors: Johnson H. D. , Kibler H. H.
Published: December 2017

A significant depression of the thyroxin I131 disappearance rate was observed in lactating Holstein cows at 80 F, 80% relative humidity (RH); 85 F, 50% RH; 85 F, 70% RH; 90 F, 40% RH; 90 F, 50% RH; and 95 F, 20% RH. Differences from values at 65 F were not significant at 80 F, 30% RH; 80 F, 50% RH; 90 F, 20% RH; and 90 F, 25% RH. At 85 F and 90 F temperatures the effect of high humidity in depressing thyroxin I131 disappearance rate was obvious. Depression of hormone and feed intake at the higher humid temperatures suggests that the depression of thyroid gland function may be related to alteration in hormonal utilization in the peripheral tissues or to a more direct temperature effect (probably neural) on both thyroid gland secretion and appetite center. Thyroxin I131 disappearance rates, feed intake and body temperatures are expressed graphically relative to a temperature humidity index (THI) (U. S. Weather Bureau). The data show some decline above a THI of 71 and a marked decline above 75.

Submitted on January 26, 1962
Rheology of blood and flow in the microcirculation
Authors: Merrill E. W. , Gilliland E. R. , Cokelet G. , Shin H. , Britten A. , Wells R. E.
Published: December 2017

Rheological properties of normal human blood as a homogeneous substance: its yield stress and the stress-shear rate function under creeping shear rates, were directly measured for the first time in a Couette type viscometer, the cylinders of which were grooved to minimize heterophase effects (defined herein). The experimental data are well fitted by the Casson equation, which implies reversible aggregation of red cells into rouleaux at low shear rates. In particular, the value of yield stress extrapolated from the Casson equation is found to be equal to the directly measured yield stress within ± 10%. The yield stress is almost independent of temperature over the range 10–37 C. The following questions related to flow in the microcirculation are considered: the relation of yield stress to pressure drop and to the critical closing pressure, the significance of the Casson model to slow flow, and use of rheological parameters in general for microcirculatory flow calculations.

Note:

(With the collaboration of C. S. Draper, P. J. Gilinson, Jr., C. R. Dauwalter, M. Grove-Rasmussen, and R. Shaw)

Submitted on July 10, 1962
Cardiorespiratory effects of large pneumothorax in conscious and anesthetized dogs
Authors: Kilburn Kaye H.
Published: December 2017

Ventilation, arterial blood gases, diffusing capacity for carbon monoxide, and flow and pressure in the pulmonary circulation were measured in conscious and pentobarbital-anesthetized dogs at intervals up to 5 hr after intrapleural injection of air. Pneumothorax of twice the functional residual capacity increased the frequency of breathing and reduced physiological dead space in both conscious and anesthetized dogs, but conscious dogs were otherwise unaffected. In contrast, the arterial blood oxygen saturation fell, pulmonary artery pressure rose, and carbon monoxide diffusing capacity was reduced in anesthetized dogs despite greatly increased respiratory minute volume and alveolar ventilation. Ventilation was depressed by anesthesia alone in controls and improved gradually during the experiments. Pentobarbital anesthesia appeared to augment cardiorespiratory depression or abolish compensatory reactions evoked by pneumothorax to produce effects in anesthetized dogs which did not occur in their conscious counterparts. The potent effects of pentobarbital anesthesia on ventilation, pulmonary circulation, and carbon monoxide diffusing capacity, emphasize the advantage of conscious subjects in cardiorespiratory studies.

Submitted on July 25, 1962
A-a difference in O2 tension and physiological dead space in normal man
Authors: Raine June M. , Bishop J. M.
Published: December 2017

Alveolar-arterial difference in oxygen tension (A-aD) and physiological dead space/tidal volume ratio (Vd/Vt) were measured in normal subjects aged 17–66 years, in the supine and sitting postures. Paoo2 decreased and A-aD increased with age. A-aD was not affected by posture, but increased with Paoo2. Regression equations relating Paoo2 and A-aD to age, and Paoo2 were calculated. Vd/Vt increased with age in the supine position, but when sitting the increase with age was small and barely significant. Consequently, although Vd/Vt was greater when sitting than when supine in young subjects, there was no such difference in the older subjects. Possible reasons for the effect of age and body position are discussed.

Submitted on August 6, 1962
Gas transfer across the skin in man
Authors: Klocke R. A. , Gurtner G. H. , Farhi L. E.
Published: December 2017

Any inert component of the inspired gas reaches the skin by the cutaneous perfusion. When part of the body is enclosed in an oxygen-filled chamber, a portion of the inert gas is transported out of the tissues into the oxygen atmosphere. The rates of helium, argon, and nitrogen transport were determined in the forearm and hand of a normal subject at ambient temperatures ranging from 18 to 43 C, analysis being performed by gas chromatography. At any temperature, the ratio Va/Vhe was found to be equal to (αa·Pa/(See PDF)a)/ (αHe·Phe/(See PDF) He) where V is the rate of gas transport, agr the solubility of the gas in blood, P the pressure of the gas in the blood, and mol wt the molecular weight of the gas. This indicates that the gas transport is limited by diffusion through the skin barrier and is affected only indirectly by changes in cutaneous blood flow in individual capillaries. Gas transport is at a minimal value at temperatures below 28 C, increasing in a linear fashion with increasing temperature above 28 C. This increase in transport shows that the increase in cutaneous perfusion at elevated ambient temperatures is accompanied by the opening of additional capillaries, the resulting increase in diffusing capacity being responsible for the increase in gas transport.

Submitted on August 6, 1962
Effect of physical exercise on blood clotting and fibrinolysis
Authors: Iatridis Sotirios G. , Ferguson John H.
Published: December 2017

The effect of strenuous exercise on the clotting and fibrinolytic systems was studied on 1 Hageman-deficient and 59 normal subjects (males aged 18–37 years). In the normal subjects there was a significant shortening of the whole-blood clotting time and of the partial thromboplastin time both in glass and in siliconized tubes. Plasma factor VIII (AHF or AHG) assays rose to 188% (average), but the specificity of the test is questioned. Factor XII (HF) increased to 318% (average) unequivocally. A postexercise increased heparin tolerance was also noted. There was no significant increase in the levels of fibrinogen, prothrombin, factor V (AcG), or factor VII (proconvertin) and factor X (Stuart). Fibrinolytic activity as measured by the euglobulin lysis and plasma plate methods increased significantly in most of the normal subjects. The data suggest that the fibrinolytic factor which increases after exercise is not active plasmin, but is related to the “activator” mechanisms. A plasma lysokinase (indirect activator) seems to preponderate in over half the cases. In 20% of cases a plasminoplastin (direct activator) may be involved. In the Hageman-deficient subject there was no improvement in clotting, and the slight changes in some of the fibrinolysis tests were nonsignificant.

Submitted on October 16, 1962

Submitted on October 16, 1962
Kinetics and mechanism of oxygen debt contraction in man
Authors: Margaria R. , Cerretelli P. , diPrampero P. E. , Massari C. , Torelli G.
Published: December 2017

Oxygen consumption, along with lactic and pyruvic acid in blood, have been measured throughout the performance of heavy muscular exercise of different intensities, all leading to exhaustion in 1–10 min. Oxygen consumption increases exponentially with time; the maximum level attained seems to be independent of the intensity of exercise except in exercises of very high intensity and short duration, when it seems to be slightly increased. The rate of increase of oxygen consumption increases with the intensity of exercise. Pyruvic acid in blood increases exponentially also, and a steady state is reached at a level which tends to be higher, the heavier the exercise. Lactic acid increases as a linear function of time, the line eventually flattening down only toward the end of the exercise when the maximal values of lactic acid are reached. The lactic acid increase, grams per minute, is a linear function of the intensity of exercise; no lactic acid is produced if the exercise is below 220 cal/kg min, or a higher value for athletes. The caloric equivalent of lactic acid production from glycogen can be calculated at about 222 cal/g. This value in man is discussed in relation to previous values given. The kinetic of the lactic acid increase during exercise is in agreement with the hypothesis of an additional (alactacid) mechanism of oxygen debt contraction.

Submitted on July 31, 1962
Alveolar gas exchange during breath holding with air
Authors: Lanphier E. H. , Rahn H.
Published: December 2017

Four normal subjects used a partial rebreathing procedure to deliver frequent alveolar gas samples during breath holding with air. In breath holding during mild exertion, O2 uptake declined steadily while CO2 transfer dropped abruptly and later ceased entirely as alveolar Pco2 reached a virtual plateau. Application of estimated instantaneous values of R provided an indication of mixed venous blood values and permitted interpretation in terms of the changing venous-alveolar-arterial relationships. Arterial Pco2 very early equaled mixed venous Pco2 and then exceeded it increasingly. The plateau of alveolar Pco2 was due in part to the fall in alveolar Po2 since decreasing O2 uptake lessened the CO2-concentrating effect of lung-volume reduction while the Pco2-elevating effect of blood oxygenation was also diminishing. However, an important slowing of the rise in mixed venous CO2 content and Pco2 was also noted and remains unexplained.

Submitted on October 17, 1962
Relation between anatomic respiratory dead space and body size and lung volume
Authors: Hart M. C. , Orzalesi M. M. , Cook C. D.
Published: December 2017

The respiratory anatomic dead space has been measured by the single breath nitrogen washout method of Fowler in 73 normal subjects ranging from 4 to 42 years of age. The volume of the anatomic dead space correlated closely with height (Vd (ml) = 7.585 x Ht (cm)2.363 x 10-4·ɣ = .917), but also with body weight, surface area, and functional residual capacity. When compared on the basis of any of these parameters there was no significant difference between the anatomic dead space values for males and females. Comparisons with available data for newborn infants suggest that the value of the anatomic dead space has a relatively constant relation to height from birth to adulthood. Dead space appears to increase more rapidly than weight, surface area, and functional residual capacity during, at least, the early period of somatic growth.

Note:

(With the Technical Assistance of J. H. Shaw)

Submitted on October 25, 1962
Respiratory responses mediated through superficial chemosensitive areas on the medulla
Authors: Mitchell R. A. , Loeschcke H. H. , Massion W. H. , Severinghaus J. W.
Published: December 2017

We have demonstrated respiratory chemosensitivity to changes in (H+) and Pco2 of the cerebrospinal fluid (CSF) in the subarachnoid space on the ventrolateral surface of the medulla. Respiratory stimulation was elicited from this region by increased Pco2 and (H+), nicotine, and acetylcholine; and respiratory depression by procaine, NaCN, lobeline, cold CSF, decreased Pco2 and (H+). CSF made acid by high (Cl-) at constant Pco2 moved the entire CO2 response curve to the left and was a more effective stimulus than normal CSF made acid by equilibration at high Pco2, presumably because of rapid diffusion loss of CO2 from the perfusing CSF into the underlying tissue and blood. Steady rapid perfusion of this area with a mock CSF of normal (H+) and Pco2 had no effect on respiration but depressed the respiratory response to inhaled CO2 by 40%. When placed in the fourth ventricle, procaine and high (H+) and Pco2 did not affect respiration, but nicotine and acetylcholine depressed it. This suggests that part of the medullary respiratory response to inhaled CO2 originates in an (H+)-sensitive surface exposed to CSF on the ventrolateral medulla.

Submitted on August 8, 1962
Circulatory responses to high altitude in the cat and rabbit
Authors: Reeves John T. , Grover Estelle B. , Grover Robert F.
Published: December 2017

Cats were taken from Denver (5,200 ft.) to Mt. Evans (14,150 ft.) anticipating that this degree of hypoxia would induce pulmonary hypertension. Rabbits were included for comparison with the cat. All cats died without developing pulmonary hypertension or right heart failure, and in spite of arterial and mixed venous O2 tensions maintained well above those of the rabbit. Presumably the cat's failure to survive was not a failure of oxygen transport to the arterial blood, or to the systemic capillaries. Paradoxically, five of eight rabbits survived despite poor arterial blood oxygenation. The rabbits developed marked polycythemia associated with modest right ventricular hypertension and dilatation.

Submitted on June 6, 1962
Metabolic and thermal response of Eskimos during muscular exertion in the cold
Authors: Andersen K. Lange , Hart J. S. , Hammel H. T. , Sabean H. B.
Published: December 2017

Performing muscular work in cold surroundings results in a greater energy requirement than that in a neutral environment at low levels of work, but is the same as that in a neutral environment at higher levels of work when rectal temperature is increased by the work. No higher heat production could be demonstrated in Eskimos than in Caucasians. It was found that rectal temperature increases during muscular work up to a certain level, this being almost constant over a wide range of environmental temperatures if the rate of work is constant. But when work rate becomes sufficiently low, the heat production is too small to compensate for the increased heat loss in the cold, so that the rectal temperature falls. A quicker onset of the rewarming of the previously cooled skin of the hands was found in Eskimos than in Caucasians as a result of exercise in the cold. This suggests a different vasomotor control of the blood supply to the skin.

Submitted on August 6, 1962
Tissue gas tensions in experimental anemia
Authors: Bartlett D. , Tenney S. M.
Published: December 2017

“Tissue-venous” O2 and CO2 tensions were determined by the subcutaneous gas pocket technique in rats with induced anemia of varying severity. Correlative ventilatory and metabolic measurements were made under light anesthesia. Gas pocket CO2 tension remained unchanged in all animals, but O2 tension decreased in anemic animals. Making use of the gas pocket tensions, rat blood nomogram, and certain assumptions, largely supported by the other measurements, a number of physiological values were calculated. From these it was concluded that in the anemic animal alveolar ventilation remained unchanged but, in the region of the gas pocket, blood flow increased with every decrement of hemoglobin concentration below the normal value. There was no “threshold” concentration of hemoglobin below normal at which point the blood flow response was initiated—the response was a continuous one. An in vivo slope value of the CO2 blood dissociation curve was derived and this was shown to vary directly with the hemoglobin concentration. Finally, the rate of disappearance of gas from the subcutaneous pocket suggested that there was a diffusion factor, in addition to blood flow, which played a role in the rate process.

Submitted on November 13, 1962
Effect of CO2 on respiration using a new method of administering CO2
Authors: Fenn Wallace O. , Craig Albert B.
Published: December 2017

When a subject inhales air containing a given concentration of CO2, the total load of CO2 is not fixed, but is increased linearly with the ventilation. The alveolar CO2 tension can never be reduced below the inspired CO2 tension, and the greater the response, the greater the CO2 load. By contrast, when CO2 is added to the inspired air stream at a constant rate, the load of CO2 and the challenge to the respiratory control is fixed and independent of the response, as it is in muscular exercise. The ventilatory response necessary to maintain a normal alveolar CO2 tension is much less with fixed amounts per minute than with fixed concentrations of inspired C02. These different methods of administering CO2 were tested in two subjects, both of whom increased their alveolar ventilation equally for the same increase in alveolar CO2 tension whether the CO2 was presented as a fixed concentration or a fixed load. Furthermore, other experiments designed to change the magnitude of the fluctuations of CO2 tension which must occur in the arterial blood during the respiratory cycle also failed to alter the subjects' ventilatory responses.

respiration control; ventilation; exercise

Submitted on January 21, 1963
Right ventricular hypertrophy in animals at high altitude
Authors: Hultgren Herbert N. , Marticorena Emilio , Miller Harry
Published: December 2017

The weight of the ventricles and septum in formalin-fixed hearts were determined in six animal species living continuously at altitudes between 10,000 and 15,400 ft in the central Peruvian Andes. Control studies were made of a similar number of hearts obtained from sea-level animals. Guinea pigs, rabbits, dogs, lambs, pigs, and steers all exhibited a moderate hypertrophy of the right ventricle roughly equivalent to a 25% increase in weight. A lesser degree of septal hypertrophy occurred in all animals except steers. The data suggest that a moderate degree of pulmonary hypertension is the probable cause of the right ventricular hypertrophy. In steers this would be roughly the equivalent of a mean pressure of 35 mm Hg at 11,800 ft compared with sea-level pressures of 24 mm Hg.

ventricular hypertrophy; altitude; pulmonary hypertension; lambs; pigs; steers

Submitted on December 3, 1962
Left ventricular ejection time index in man
Authors: Weissler Arnold M. , Harris Leonard C. , White George D.
Published: December 2017

The present studies were undertaken in an attempt to formulate an accurate expression of the relationship between the duration of left ventricular ejection and heart rate in man. On the basis of regression equations relating the duration of left ventricular ejection and heart rate in normal individuals, the index LVET + .0016 HR was derived and tested in normal adults and prepubertal children. The left ventricular ejection time index (ETI) remained constant and reproducible over the range of heart rate from 50 to 150 and yielded more consistent values in this range of heart rate than did previously derived equations. A slight but significantly higher value of the ETI was present in the adult females when compared to the adult males, while no significant difference according to sex was apparent in the children. A decrease in ETI was found when cardiac output was diminished in normal individuals during 60° head-up tilt and in patients with congestive heart failure. Of note was the finding of a significant correlation between the level of the ETI and the cardiac output in these situations.

Submitted on December 13, 1962
Hemodynamics of collapsible vessels with tone: the vascular waterfall
Authors: Permutt S. , Riley R. L.
Published: December 2017

A theoretical analysis is presented of pressure-flow relationships in arterioles based on the assumption that the presence of active tension produced by smooth muscle contraction causes a critical closing pressure which is itself a function of the magnitude of the active tension. This analysis differs from those previously carried out in that it uses the pressure-flow relationships of a waterfall rather than those described by Poiseuille's law to characterize the flow between arterioles and capillaries in the presence of active tension. It is suggested that, under some conditions, the driving pressure for the flow through arterioles is not the difference between the inflow pressure and outflow pressure of the arterioles, but rather the difference between the inflow pressure and the critical closing pressure. This seemingly slight modification causes marked differences in the interpretation of pressure-flow relationships and vascular resistance in the presence of active tone.

Submitted on December 10, 1962
Seasonal variation of magnesium and calcium in serum of the hypothermic rat
Authors: Nowell N. W. , White D. C.
Published: December 2017

Records of changes in blood Mg and Ca during body cooling are conflicting. Although a rise in serum magnesium is established in hibernators and with less certainty in artificially cooled animals, some workers have associated these changes with CO2 accumulation. In the present experiments rats were cooled to a rectal temperature of 15 C with artificial respiration to prevent CO2 accumulation. Cardiac arrest did not occur. A mean 24% rise in serum magnesium was found in the winter months. A fall occurred in the summer but the mean figure for these months was not significant. No change in the calcium levels was observed. The possible significance of the findings is discussed.

Submitted on June 1, 1962
Effect of repeated exercise on the lesser circulation
Authors: Widimsky Jiri , Berglund Erik , Malmberg Rolf
Published: December 2017

In four healthy subjects and four patients with lung disease, hemodynamic studies were done during two periods of identical exercise, 1 hr apart. Pulmonary artery pressure was lower in the second exercise period in all subjects studied. Pulmonary arterial wedge pressure was measured in four cases and was unchanged or even slightly increased. The “total pulmonary” and pulmonary vascular resistances were markedly lower in the second exercise period. The decrease in pulmonary artery pressure was found also in the second postexercise period when compared with the starting resting level. It is believed that this fall in pulmonary artery pressure and resistance was due to opening or widening of previously closed or constricted lung vessels. Repeated exercise must be used with caution when studying the effect of pharmacological or physiological agents on the lesser circulation.

Submitted on November 30, 1962
Increase in fibrinolytic activity by venous occlusion
Authors: Holemans Rudolf
Published: December 2017

Venous occlusion for 10 min, by a sphygmomanometer cuff applied above the elbow and maintained at a pressure midway between systolic and diastolic pressure, increases the fibrinolytic activity of the blood within the occluded part of the arm. In six normal human subjects the magnitude of this increase was compared with changes in blood cellular elements, plasma protein concentration, plasma antifibrinolytic activity, and plasma levels of glutamic-oxalacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT). The increase in fibrinolytic activity of the euglobulin fraction of the plasma was 3–20 times larger than the increase in plasma protein concentration and 8–24 times larger than the increase in hematocrit. Venous occlusion produced a rise in antiplasmin and antiurokinase activity of the plasma. The level of GOT in the plasma rose significantly more than the plasma protein concentration. These observations tend to indicate that the activation of fibrinolysis during venous occlusion is brought about by the release of intracellular enzyme(s).

fibrinolytic activity of blood; euglobulins; antiplasmin; antiurokinase

Submitted on May 31, 1963
Temperature regulation by hypothalamic proportional control with an adjustable set point
Authors: Hammel H. T. , Jackson D. C. , Stolwijk J. A. J. , Hardy J. D. , Stromme S. B.
Published: December 2017

The role of the hypothalamic and skin temperatures in controlling the thermal response of a resting animal was studied by measurements of 1) hypothalamic, rectal, ear skin, and trunk skin temperatures on the resting dog and rhesus monkey in hot, neutral, and cold environments; and 2) the thermal and metabolic responses of a dog in neutral and cold environments during and immediately after holding the hypothalamus at approximately 39.0 C by means of six thermodes surrounding the hypothalamus and perfused with water. The results indicate that 1) a resting animal shivers in a cold environment with the same or higher hypothalamic temperature as the same animal in a neutral environment; 2) a resting animal pants in a hot environment with the same or lower hypothalamic temperature as the same animal in a neutral environment; 3) the hypothalamus is nonetheless strongly responsive to an increase or decrease of 1 C; 4) the rate of heat loss increases at the onset of sleep while the hypothalamic temperature is falling; 5) the hypothalamic temperature is 1–2 C lower during sleep even though thermoregulatory responses are the same as when awake; 6) the rate of heat loss decreases upon awakening while the hypothalamic temperature is rising. The discussion of these results includes a suggestion that the set point for temperature regulation is 1) decreased by a rising or elevated skin and extrahypothalamic core temperature, 2) increased by a falling or lowered skin and extrahypothalamic core temperature, 3) decreased upon entering and during sleep and is increased upon awakening.

hypothalamic temperature; temperature set point; hypothalamic stimulation; dog temperature regulation; monkey temperature regulation

Submitted on October 15, 1962
Viscosity of normal human blood under normothermic and hypothermic conditions
Authors: Rand Peter W. , Lacombe Eleanor , Hunt Hamilton E. , Austin William H.
Published: December 2017

Although blood viscosity varies in relation to shear rate, hematocrit, and temperature, equipment is now available with which it may be measured in respect to each of these variables. A simple, clinically practical technique for such measurement is presented. Blood from 60 normal subjects was adjusted to hematocrits 0, 20, 40, 60, and 80, and the viscosity-shear rate relationships measured at 37.0, 32.0, 27.0, and 22.0 C. The data obtained are presented as a reference for future studies using this method. Technical details are discussed and some deserving areas of application are considered.

shear rate; cone-plate viscometer; hematocrit-viscosity relationships; blood, plasma; hematocrit; temperature; blood flow impedance; perfusion; shock; oliguria; dyspnea; coma; heart surgery; blood rheology; metabolism

Submitted on May 31, 1963
Effect of a brief contraction of forearm muscles on forearm blood flow
Authors: Corcondilas Adrian , Koroxenidis Gabriel T. , Shepherd John T.
Published: December 2017

With the use of a strain-gauge plethysmograph, the effect of a brief (0.3 sec) contraction of the forearm muscles on forearm blood flow has been studied in eight healthy adults. An increase in flow due to dilatation of the muscle vessels could be detected within a second after the completion of the contraction. This increase was proportional to the strength of the contraction. The blood flow was maximal immediately and decreased rapidly. A second contraction of the same magnitude made during the period of increased flow caused an additional increase in flow. The maximal increase in flow caused by a strong brief contraction was only about 25% of that recorded after strong repeated rhythmic contractions or a sustained contraction. Cervical sympathectomy did not change these findings, indicating the local nature of the response. Since breathing oxygen failed to reduce the dilatation for a given strength of contraction, it is unlikely that oxygen lack was the stimulus for vasodilatation. The oxygen saturation of blood that drained the muscles could not be determined accurately immediately after contraction because at this time, muscle venous blood was contaminated by venous blood from the skin.

exercise-induced vasodilatation; local mechanism of vasodilatation; venous O2 saturation during muscle contraction; brachial arterial pressure during vasodilatation; speed of muscle vasodilatation

Submitted on May 8, 1963
Oxygen consumption during three yoga-type breathing patterns
Authors: Miles Walter R.
Published: December 2017

Short periods of conscious control of the rate and depth of breathing as a health-promoting exercise has claimed wide human interest. In India, yoga cults based in part on persevering efforts to achieve physiological control of bodily functions have included systems for the control of respiration. Such breathing patterns have a long history, but have received little scientific attention. This paper reports a large series of repeated yoga respiration tests, graphically recorded under laboratory conditions by an Indian man who served as subject. The study was made by means of basal metabolism technique, employing the Krogh recording spirometer. All three of the yoga breathing patterns examined, when individually continued for 20 min or more and compared with previous relaxed quiet breathing, were found to demand an increased oxygen consumption of a mere 12–35% above basal need. The relaxed breathing that immediately followed a yoga pattern gave little or no indication that the subject had been exerting himself. There is some indication that such respiratory training may have elements in common with adaptation to high altitude and may serve to fortify an individual against the early onset of hypoxia in emergencies concerned with oxygen supply.

respiration training exercises; BMR during trained respiratory behavior; respiratory measurements during yogic breathing; thoracic and abdominal breathing; breathing patterns versus breathing rates; yogic breathing patterns; voluntary pause after inspiration; domestication of respiration; discipline for the diaphragm; higher education for the respiratory center

Submitted on February 21, 1963
Improved technique for estimating pleural pressure from esophageal balloons
Authors: Milic-Emili J. , Mead J. , Turner J. M. , Glauser E. M.
Published: December 2017

Esophageal pressure has been measured in eight healthy men during breath holding (glottis open) at various fixed lung volumes with a rubber balloon (length: 10 cm; perimeter: 3.5 cm; wall thickness: ca. 0.06 mm) containing various volumes of air. The tip of the balloon was placed at a constant distance of 45 cm from the nares. Esophageal pressure was found to increase with balloon volume at all lung volumes but not uniformly, the effect of balloon volume being greatest at both extremes of the vital capacity. As a result, lung volume-pressure curves obtained from balloons containing volumes of gas such as are commonly used are distorted. One can avoid these distortions by repeating measurements at different balloon volumes and extrapolating esophageal pressure to zero balloon volume, or by making measurements at very small balloon volumes. A close approximation of the extrapolated pressures was obtained with the present balloon containing 0.2 ml air. The esophageal pressures at or near zero balloon volume probably reflect closely local absolute pleural pressures over the full vital capacity range in some subjects and above 20% of the vital capacity in most subjects.

lung volume-pressure curves

Submitted on August 13, 1963
Screen filtration pressure method and adhesiveness and aggregation of blood cells
Authors: Swank Roy L. , Roth John G. , Jansen Jerold
Published: December 2017

An apparatus is described which measures the resistance to flow of blood through a screen with multiple openings 20 μ square. This apparatus is especially sensitive to presence in blood of aggregated blood elements and adhesive materials. It is much less sensitive to changes in hematocrit. The structural features and operation, as well as interpretation of pressure curves are described.

viscosity of blood; suspension stability of blood; aggregation of platelets and leucocytes; aggregation of red blood cells; adhesiveness of platelets; adhesiveness of blood elements

Submitted on August 5, 1963
Ventilation standards for small mammals
Authors: Kleinman Leonard I. , Radford Edward P.
Published: December 2017

Ventilation standards for small mammals have been prepared on the basis of the relationship between alveolar ventilation and metabolism. On the assumptions of an average respiratory quotient of 0.85 and physiological dead space directly proportional to tidal volume, the relationship between tidal volume, breathing frequency, and body weight has been derived. The standards are presented in a graphic form and as a slide rule.

animal ventilation; artificial respiration; tidal volume, breathing frequency and body weight relationship

Submitted on August 15, 1963
Olfactory analogue to directional hearing
Authors: von Békésy Georg
Published: December 2017

The direction of a sound source can be determined binaurally by using the time difference and the loudness difference of the sound waves arriving at the two ears. Similarly, the direction of an olfactory source can be determined by using the time difference and the difference in sensation magnitude of the olfactory stimuli between the two nostrils as the air surrounding the odorous object is inhaled. Time differences of the order of 0.1 msec can be recognized—a value similar to that found in hearing. Thus the direction of an odor can be determined with a precision of 7–10° in spite of the small distance between the nostrils compared to the distance between the ears. In this respect, there is very little difference between observations made with such odorants as benzol, eucalyptus, cloves, and lavender. The existence of an analogy between hearing and smelling may help to delineate some electrophysiological correlates of the directional sensation, which is so well developed in both senses.

localization of olfactory stimuli; interaction between the two nostrils during smelling; time pattern and olfactory localization; olfactory sensation magnitude and duration of stimulus; combination of smell and taste into a single sensation

Submitted on November 1, 1963
Muscular exercise at great altitudes
Authors: Pugh L. G. C. E. , Gill M. B. , Lahiri S. , Milledge J. S. , Ward M. P. , West J. B.
Published: December 2017

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

respiration, work and altitude; ventilation, work and altitude; heart rate, work and altitude; O2 transport system at high altitudes; altitude acclimatization

Submitted on July 29, 1963
Respiratory sinus arrhythmia: a frequency dependent phenomenon
Authors: Angelone Alfonso , Coulter Norman A.
Published: December 2017

An examination of respiratory sinus arrhythmia is presented. Sinusoidal breathing was varied over a wide frequency range and the amplitude and phase of the accompanying fluctuations of heart rate were observed. These data show that heart rate is not necessarily in phase with respiration as previously described, but rather that the phase angle between heart rate fluctuations and respiration varies with frequency of breathing in a characteristic fashion. The usual descriptions of respiratory sinus arrhythmia are judged to be inadequate since they are shown to represent only a single point on the entire frequency response curve correlating breathing rate with sinus arrhythmia.

heart rate fluctuation and respiratory frequency in man; frequency amplitude analysis of respiration-heart rate relationship; heart rate versus breathing: amplitude and phase angle; breathing-induced heart rate changes: phase angle; respiration-induced heart rate changes: phase angle respiratory sinus arrhythmia; respiration versus heart rate: amplitude and phase angle; sinus arrythmia and respiration: amplitude and phase angle

Submitted on July 22, 1963
Carbon monoxide in blood: analytical method and sources of error
Authors: Coburn R. F. , Danielson G. K. , Blakemore W. S. , Forster R. E.
Published: December 2017

A method is described for the analysis of small concentrations of carboxyhemoglobin in blood in which the CO is dissociated from the hemoglobin by oxidizing the latter to methemoglobin with ferricyanide and measured as a gas in an infrared analyzer. The method has a sd of ±0.006 ml/100 ml in the range from 0.1 to 1.0 ml/100 ml. Data are presented which indicate that CO can be formed in a blood sample in vitro if the temperature during oxidation with ferricyanide is higher than about 60 C, if the pH of the reacting solution is 10 or higher, and if metallic mercury is not present during the reaction. It was demonstrated that additional CO is not formed during the analysis with the method described and that the method is highly specific for CO.

blood carboxyhemoglobin; carbon monoxide; blood gases; carbon monoxide production; hemoglobin oxidation

Submitted on July 19, 1963
A new weighting system for mean surface temperature of the human body
Authors: Ramanathan N. L.
Published: December 2017

On the basis of an analysis of the skin temperature data on three resting human subjects from 112 experiments, a simple weighting system for computing the mean skin temperature from observations on four areas of the body, namely, chest, arms, thighs, and legs, has been proposed. The proposed system of weighting yields mean skin temperature values identical with the elaborate Hardy-Dubois weighting formula. The value of the medial thigh temperature as an index of the mean skin temperature has also been investigated and discussed.

skin temperature measurement

Submitted on May 20, 1963
Effect of alterations in end-tidal CO2 tension on flow resistance
Authors: Newhouse Michael T. , Becklake Margaret R. , Macklem Peter T. , McGregor Maurice
Published: December 2017

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

PaCOCO2; work of breathing; mechanical properties

Submitted on June 24, 1963