bluuebunny/crossref_metadata_2025 huggingface dataset:
Physiological alterations in increased pulmonary blood flow with and without pulmonary hypertension
Authors: Ellison Lois T. , Hall David P. , Yeh Thomas , Mobarhan H. , Rossi Joseph , Ellison Robert G.
Published: December 2017

Alterations in pulmonary function and in hemodynamics were studied in dogs with high pulmonary blood flow resulting from systemic pulmonary artery shunts. In order to facilitate elevation in pulmonary artery pressure, the vascular bed was reduced in some cases by obstructing branches of the pulmonary artery with Teflon clips or by lobectomy. Results in 30 control dogs and in 30 animals that survived 5–36 months (average 16) following creation of shunts indicated that pulmonary function was not significantly altered by increased pulmonary blood flow until pulmonary artery hypertension developed. When systolic pulmonary artery pressure exceeded 40 mm Hg, there was a decrease in arterial Po2, an increase in venous admixture percentage of cardiac output, and an increase in the A-a O2 difference during three levels of O2 breathing, indicating both abnormal venous admixture and abnormal diffusion. Possible explanations for these findings are presented. Evidence in one dog suggests that these alterations are reversible.

Submitted on August 10, 1960
Tritium used for estimation of right-to-left shunts
Authors: Lassen Niels A. , Mellemgaard K. , Georg J.
Published: December 2017

A method is described for estimating right-to-left shunts through the determination of the recovery of intravenously injected tritium gas in the arterial blood. Tritiated water was used as an indicator of the dilution that would have occurred had no loss of tritium gas taken place in the alveoli. In normal man, average recovery values obtained were: 1.1% during normal respiration, 0.6% during hyperventilation, 0.9% during inspiratory apnea and 1.8% during expiratory apnea. In two patients with congenital heart disease large recovery values were found with right-to-left shunt, agreeing with the shunt estimates obtained using oxygen analysis. While no significant diffusion limitation at the alveolar membrane can be supposed to occur normally, a significant back pressure results from the gradually increasing alveolar tritium concentration. This factor is presumably responsible for the greater part of the recovery found in normal man, while a smaller part may be due to actual bypassing of the alveoli. On the basis of the experiments it is estimated that in normal man 0.3% of the blood entering the right side of the heart reaches the left side without passing air-filled alveoli.

Submitted on November 5, 1960
Prediction of skin temperature of men in the cold
Authors: Iampietro P. F.
Published: December 2017

Skin temperatures of seminude men were measured during 2-hr exposures to various combinations of air temperature (90–25 F) and wind velocities (< 1, 5, 10 mph). The data were used to derive an expression for the estimation of mean weighted skin temperature as a function of duration of exposure (up to 180 min), air temperature (90 to -20 F), and windspeed (0–40 mph). A chart was also constructed for more rapid estimation of skin temperature.

Submitted on August 17, 1960
Basal metabolic rate and body composition at high altitudes
Authors: Picó;n-Reátegui E.
Published: December 2017

Basal metabolic rate (BMR) and body composition were determined in 17 healthy adult males living at an altitude of 14,900 ft above sea level. Using body surface area as a standard of reference and following the criterion of Boothby et al. ( Am. J. Physiol. 116: 468, 1936), the BMR of the high-altitude resident fell within the limits considered normal for healthy adults at sea level. A comparison with the data obtained by investigators in the United States and in India shows that, when either fat-free body mass (FFM), cell mass (C), or cell solids (S) are the standard of reference, the BMR is higher in the high-altitude resident. The higher O2 consumption per kilogram of FFM, C, or S in the high-altitude resident seems to be one of the many mechanisms developed by the body in its process of adaptation to the low O2 tension.

Note:

(With the Technical Assistance of Melquiades Huayna-Vera)

Submitted on October 24, 1960
Unequal distribution of pulmonary diffusing capacity in the anesthetized dog
Authors: Piiper Johannes , Haab Pierre , Rahn Hermann
Published: December 2017

In anesthetized dogs the alveolar-arterial O2 pressure difference (AaD) was measured at alveolar O2 pressures of 45, 75, 106, 146, and 255 mm Hg. The AaD values observed could not be explained by the conventional “shunt factor,” “diffusion-limitation factor,” or “distribution factor.” However, the experimental data could be explained on the basis of the concept of unequal distribution of pulmonary diffusing capacity, D, to perfusion, Q. A procedure for estimation of the pattern of distribution of D to Q from experimental data is described. The results were compatible with the assumption that the lung consisted of a minimum of three functional compartments characterized by different D/Q ratios. A small portion of the perfusion (1.5%) probably behaved like a true shunt (D/Q = 0); 13% of the pulmonary blood flow passed through a compartment that shared in 2% of the total diffusing capacity only, resulting in a relatively small D/Q ratio for this compartment. The presence of this compartment gave rise to the largest part of the AaD at air breathing. The calculated D/Q value for the remaining, major compartment was so high that a measurable AaD due to diffusion limitation in this compartment could occur only at alveolar O2 pressures lower than 60 mm Hg. The validity of the assumptions and the significance of the results are discussed.

Submitted on May 23, 1960
Equation for inert gas exchange which treats ventilation as cyclic
Authors: Riggs Douglas S. , Goldstein Avram
Published: December 2017

When a constant concentration of an inert gas is inhaled, the rate at which the equilibrium quantity of the gas in blood and tissues is approached depends upon many factors. In previous mathematical descriptions of this process, ventilation has been assumed to be continuous. In the present analysis, respiration is treated as cyclic, and an equation for the time needed to achieve any given proportion of equilibrium is derived. This equation is a complex function of eight variables. However, two of these, the functional residual capacity and the volume of lung tissue, are of negligible importance. Furthermore, an n-fold increase in rate of respiration has almost the same effect upon the calculated rate of approach to equilibrium as an n-fold increase in alveolar ventilation per breath. The assumption that ventilation is continuous is therefore a legitimate simplification, and the complex equation has no practical advantage over a much less intricate formulation.

Submitted on October 13, 1960
Urinary excretion of hippuric acid by man
Authors: Wu Hsien , Elliott Howard C.
Published: December 2017

A simplified scheme for interpretation of urinary hippuric acid excretion data in terms of consecutive irreversible first-order processes is presented. The rate of excretion of endogenous hippuric, uric, and glucuronic acids is constant under the conditions of the experiments. The average value for the excretion constant KE for exogenous hippuric acid has been determined to be 2.7 hr-1 (0.0452 min-1) for doses of sodium hippurate ranging from 1 to 4 mEq. The average Ks for synthesis of hippurate from benzoate is 10.5 hr-1 (0.175 min-1) for doses of sodium benzoate ranging from 1 to 4 mEq. Study of 17 patients with varying degrees of renal disease as confirmed by standard p-aminohippurate and inulin clearances indicates that the determination of KE may be of value in the study of renal function, particularly where standard clearance techniques are not available. Preliminary data indicate that Ks may be useful in the study of the delay in synthesis of hippurate from benzoate that has been observed in some cases of liver pathology.

Submitted on August 29, 1960
Effect of environmental temperature and humidity on intake and digestion of nutrients
Authors: Sharma D. C. , Kehar N. D.
Published: December 2017

The intake and digestion of nutrients were measured in growing heifers of a good breed imported into a region of hot and humid climate notorious for the unthrifty condition of its cattle. The control group was maintained on the home tract of these animals. Effect of regional feeds, climate and seasons on feed and water intakes, digestibility of certain proximate principles and balances were studied to assess the extent to which alimentation becomes involved in the physiological adjustments to environments. The control group had a higher intake of feed, digestibility of dry matter, crude protein, ether extract and total carbohydrates, and balance of nitrogen than its counterpart on the same diet in a hot and humid area. Between the imported and local diet the animals preferred the diet of their home area. In all three groups there was a highly significant effect due to seasons. The interaction between group and season was also significant.

Submitted on January 9, 1961
Estimation of heat flow from hands of Eskimos by calorimetry
Authors: Hildes J. A. , Irving Laurence , Hart J. S.
Published: December 2017

Heat flow from hands immersed in cold water was studied in nine Eskimo and four white subjects. To assess the loss of heat from the hand circulation, the change in heat content of the hand during cold water immersion was first calculated from derived average hand temperatures. After 30 min cold water immersion, average hand temperatures were found to be approximately 6.5 C higher than the water. Derived values for circulatory heat loss averaged 15,564 cal for the Eskimos and 13,815 cal for the white subjects when the room temperature was 25 ± 2 C, and 11,167 cal and 10,610 cal, respectively, when the room temperature was 15 ± 2 C. However, an inverse relationship between hand volume and heat flow per 100 ml hand was found, and when considered on this basis no difference could be made out between the two groups although the number of subjects was too small for statistical comparison. The possibility that differences reported in the literature between groups of subjects are related to differences in hand size is discussed.

Submitted on January 23, 1961
Effects of oxygen inhalation on responses to cold exposure
Authors: Maccanon D. M. , Eitzman D. D.
Published: December 2017

The effects of oxygen inhalation on shivering and thermal and metabolic responses to exposure to cold (10 C) were determined in ten healthy male subjects. The results showed that oxygen breathing reduced shivering and promoted a feeling of greater comfort. The ventilatory response to cold was diminished, and oxygen consumption was significantly lower during the later periods of the cold exposure. Carbon dioxide production was reduced and the mobilization of nitrogen during the initial periods of cold exposure was also noted. Since body temperatures and their rates of fall were not significantly altered by oxygen inhalation, a shift to more efficient metabolic heat production seems indicated.

Submitted on February 6, 1961
Experimental hypoxemia in older and younger healthy men
Authors: Simonson Ernst
Published: December 2017

Arterial oxygen saturation was measured by means of an earlobe oximeter in 68 older (mean age 59.5) and 58 younger, (mean age 23.4 years) healthy men while breathing a 10% O2, 90% N2 mixture for a period of 10 min. The drop of the arterial oxygen saturation was more pronounced in the older men, and the difference in reaction was statistically highly significant.

Submitted on January 9, 1961
Biological applications of kinetic analysis of a two-compartment open system
Authors: Shore Moris L.
Published: December 2017

Complex metabolic steady state systems in which a central compartment (blood) exchanges compound with independent peripheral compartments (tissues), with synthesis and loss of compound occurring in the system, are examined. Factors that result in the simplification of complex biological systems into two-compartment open systems are discussed. Equations are derived for the two-compartment open system which allow calculation of: compartment size for central and combined peripheral compartments, total rate of exchange between these compartments, and total rate of synthesis and loss of compound from the system. Data required for these calculations can be obtained with relative ease from the accessible central compartment. Thus, a tracer dose of labeled compound is introduced into the central compartment and the specific activity-time relations of the compound are determined. Values derived by graphical analysis of this curve and knowledge of the dose of labeled compound administered are the only primary data needed to determine the parameters of the system. Practical applications of this analysis to model and biological systems are presented.

Submitted on March 13, 1961
Delay of twitch relaxation induced by stress and stress relaxation
Authors: Walker Sheppard M.
Published: December 2017

The triceps surae of male rats was prepared in situ for isometric and isotonic recording and for stimulation through the cut sciatic nerve. Relaxation in isometric twitches is markedly delayed in muscle showing high resting tension. The time course of the delayed twitch relaxation is similar to that of stress relaxation in quickly stretched resting muscle. Delay of twitch relaxation is exaggerated in experiments with quick release and foreloading. The findings led to the following conclusions: a) the parallel elastic elements, in muscle with resting tension, lose stress during shortening of contractile elements and regain stress during relaxation of contractile elements. b) The exaggerated delay of twitch relaxation, produced in quick release experiments, is due to increased stress and stress relaxation made possible by enhanced release from stress in the preceding contraction phase of the twitch. c) Stress relaxation in parallel elastic elements accounts for the observed delay of twitch relaxation in muscle with resting tension.

Submitted on January 30, 1961
Effect of prolonged bodily hydration on the renal concentrating operation
Authors: Yoon Myong Cho , Hong Suk Ki
Published: December 2017

The maximal renal concentrating ability was studied in six healthy men while 150 ml water/kg body wt. was forced daily for 9 days. The maximally concentrated urine samples were obtained after intramuscular injection of 5 units of surgical Pituitrin on the 3rd, 6th, and 9th day of the forced hydration period. The renal concentrating ability was already reduced on the 3rd day of the forced hydration, and there was very little further reduction during the subsequent period. All urinary constituents lost concentration in parallel. The rates of excretion of various urinary constituents through maximally concentrated urine did not show any consistent change. Moreover, all impairments were reversible and were not accompanied by any alteration in the glomerular filtration rate. It is thus considered that the observed reduction in renal concentrating ability during the forced hydration period is due to the reduction of tubular function. It is postulated that the collecting duct undergoes a certain mechanical deformation during the forced hydration period and, hence, is not able to perform the concentrating operation as much as it would do otherwise.

Submitted on August 10, 1961
A graphical analysis of thoracoabdominal mechanics during the breathing cycle
Authors: Agostoni Emilio
Published: December 2017

A graphical analysis of the mechanical contribution of the thoracic and abdominal components during different kinds of breathing cycles has been made. The lung volume has been plotted against the dynamic pressures above and below the diaphragm; the intrathoracic pressures due to the elasticity of the lung and of the chest were also represented on the same diagrams. The transdiaphragmatic and the transabdominal pressures have been thus studied and compared with the pressures exerted by the inspiratory and expiratory muscles as given by transthoracic pressure measurements.

Submitted on February 27, 1961
Equilibrium distribution of radioxenon in tissue: xenon-hemoglobin association curve
Authors: Conn Hadley L.
Published: December 2017

In vitro and in vivo studies were made of the equilibrium distribution of radioxenon in various organs and tissues of the dog and the xenon uptake compared with a water standard. Tissue-blood partition coefficients were calculated. The radioxenon-hemoglobin association curve was determined for dog and human hemoglobin and methemoglobin. The uptake of radioxenon by blood, due in particular to xenon-hemoglobin affinity, was appreciably greater than uptake either by water or by most other body tissues. Fat and brain were notable exceptions. Consequently, tissue-blood partition coefficients were about eight for fat, one for brain, and significantly less than one for other tissues studied. Acceptable accuracy for blood flow determinations with a radioxenon inert gas diffusion method would seem to depend on the use of a partition coefficient correction in turn corrected at least for the existing hemoglobin concentration. The uptake of xenon by hemoglobin had the characteristics of a solubility or a quasi-solubility phenomenon. The problem of the nature of the interaction is apparently not resolved.

Submitted on June 19, 1961
Assessment of liver function in mice with Bromsulphalein
Authors: Kutob S. David , Plaa Gabriel L.
Published: December 2017

The Bromsulphalein method of Casals and Olitsky has been modified to increase its sensitivity. The modification, based on time-disappearance curves, consists of employing a 100 mg/kg intravenous dose of Bromsulphalein and an interval of 15 or 30 min before sampling. Comparative studies were made on mice treated with CCl4 or CHCl3. The new method was much more sensitive than the original. When the results were compared to those obtained by histologic examination, it was found that the new method had a sensitivity about equal to that of customary histologic examination. The hepatotoxic properties of seven other halogenated methane derivatives were determined. The dihalogen compounds failed to exhibit signs of liver involvement.

Submitted on July 31, 1961
An electrical caliper for continuous measurement of relative displacement
Authors: Mallos Alexander J.
Published: December 2017

An electrical recording caliper for the continuous measurement of relative displacement has been developed. The details of design, operation, and performance are described. The frequency response was uniform (±5%) through 25 cycle/sec. An approximately 0.5% error related to the mechanical impedance of the device was estimated to occur. The system is linear and free of hysteresis. Base-line and gain stability are acceptable.

Submitted on July 21, 1961
Pulmonary hysteresis
Authors: Cavagna G. , Brandi G. , Saibene F. , Torelli G.
Published: December 2017

The pressure-volume (P-V) diagram of the human lung was recorded on three subjects at minute ventilation from 2.5 to 180 liters/min. The area included between the inspiratory and expiratory curve is the expression of the work necessary to overcome a) airway resistance to the flow, b) lung viscosity, and c) eventual pulmonary hysteresis. From the experimental data the mean pressure (Pm) and the mean flow (Vm) have been calculated, and the mean pressure plotted against the mean flow; the extrapolation of the Pm data to Vm = o leads to a positive value of Pm of 0.5-0.9 cm H2O, and this is interpreted as being due to pulmonary hysteresis. This is almost equal to the pressure necessary to overcome the airway resistance and the lung viscosity during respiration at rest.

Submitted on April 17, 1961
Peripheral blood flow as an indicator of emotional reaction
Authors: Vanderhoof Ellen , Clancy John
Published: December 2017

In order to study the effects of emotional stress on peripheral blood flow, subjects were exposed to a variety of stresses while blood flow was measured plethysmographically. Stressful situations included abreaction of some previously experienced traumatic event and exposure to new stresses in both the awake and hypnotic states. During recall of traumatic experiences under hypnosis the change in mean blood flow was an increase over control flow for all subjects. Initially subjects responded to new stresses with an increase in blood flow but repetition of the stress extinguished the response. An interpretation of these results in terms of personality functioning is discussed. Blood flow, as measured by venous occlusion plethysmography, seems to be a sensitive indicator of emotional reactivity and may have considerable usefulness in clinical investigation of psychiatric patients.

Submitted on July 12, 1961
Limb tourniquet and intramuscular clostridial toxin effects on renal function
Authors: Nickel James F. , Gagnon John A. , Levine Leonard
Published: December 2017

Eight anesthetized dogs, given Clostridium perfringens type A toxic filtrate into the hind-limb muscles, showed severe spreading edema, hemoconcentration, marked reduction in para-aminohippurate (PAH) and creatinine clearances, and a rise in the renal vascular resistance. In the first 4 hr sodium excretion fell sharply, and mean arterial blood pressure, slightly. In eight similar dogs venous-occlusive pneumatic tourniquets were applied high on both hind limbs for 90 min. Edema was localized and minimal. Hematocrit was unchanged. PAH and creatinine clearances were extremely low in the second 30-min period of the occlusion but had risen somewhat in the last 30-min period. Sodium excretion was greatly reduced. Arterial pressure and vascular resistance rose very significantly. Upon removal of the tourniquets, PAH and creatinine clearances, blood pressure, and renal vascular resistance returned toward normal. Sodium excretion continued to fall. In many respects the renal changes resulting from two different forms of peripheral trauma are similar.

Submitted on August 14, 1959
Renal diurnal cycle in hydropenic man
Authors: Hulet William H. , Richardson John R.
Published: December 2017

Ten hydropenic male subjects, 29–60 yr of age and without evidence of cardiovascular-renal disease, were examined with respect to renal function during the period 8:30 am-10:30 am. No infusions were given and because of the oliguric state of the subjects, the utmost care was used in emptying the bladder by catheter and air washout. The subjects remained recumbent in bed from the time of awakening until transferred by litter to the research unit, where they remained in the supine position throughout the test. The rate of sodium excretion remained essentially constant throughout the study period, an event contrary to the expected increase in sodium excretion due to the diurnal cycle and possibly related to the hydropenic state of our subjects. No evidence was obtained in these continuously recumbent subjects that a diurnal rhythm in sodium excretion extends into the mid-morning hours.

Submitted on June 30, 1961
Uptake of oxygen-15-labeled CO2 compared with carbon-11-labeled CO2 in the lung
Authors: West J. B. , Dollery C. T.
Published: December 2017

Carbon dioxide labeled with oxygen 15 has been used to measure regional blood flow in the lung by counting over the chest during a short breath-holding period following a single breath of the gas. This gas has been found to exhibit different physiological behavior from carbon-11-labeled CO2. For example, the clearance rates of the oxygen-labeled gas are about twice as fast as those of carbon-labeled CO2. Measurements on alveolar gas expired immediately after inspiration of active gas show that the oxygen-labeled gas disappears from the alveoli about ten times faster than its carbon-labeled counterpart. In addition, if venous blood is drawn shortly after a breath of oxygen-labeled CO2, the activity cannot be removed from the blood by adding acid and shaking under vacuum, whereas the expected loss of activity occurs for carbon-labeled gas. These apparent discrepancies can be explained by exchange between the oxygen atoms of water and bicarbonate after the gas has been taken up by the blood. In vitro measurements show that the uptake of oxygen-labeled CO2 into blood can be reduced by adding carbonic anhydrase inhibitor. The results affect the interpretation of the clearance rates of other radioactive gases in the lung.

Submitted on December 7, 1960
Loss of functional residual capacity in poliomyelitis
Authors: Faerber Irene , Liebert Peter B. , Suskind Mitzi
Published: December 2017

Vital capacity, expiratory reserve volume, and functional residual capacity were determined on 11 normal controls and 25 postpoliomyelitis patients with a chronic flaccid respiratory paralysis. In general, the expiratory reserve volume diminished concomitantly with the vital capacity. As the residual volume was the same in the two groups the lost expiratory reserve volume of the patients had not been added to it. The expiratory reserve volume and functional residual capacity were significantly smaller in the patient group than in the controls. Relaxation pressure-volume curves determined for ten patients and eight controls indicated a loss of compliance of the thoracopulmonic unit of the patients somewhat greater than would be expected from the smaller functional residual capacity, implying some loss of elasticity in the lungs and/or chest wall in the disease process.

Submitted on November 17, 1960
Acceleration protection by means of stimulation of reticuloendothelial system
Authors: Stiehm E. R.
Published: December 2017

Stimulation of the reticuloendothelial system (RES) in rats was found to be effective in enhancing the tolerance to high g acceleration stress. Utilizing 10 daily consecutive intraperitoneal injections of endotoxin at increasing doses from 100 to 1200 μg, the median survival time of 122 rats undergoing 20 positive g acceleration was increased from a control level of 9.7 min to 14.2 min. One group of 48 rats had a median survival of 23.6 min compared to a control level of 11.3 min. The protective action of RES stimulation and the inhibitory action of RES blockade were found to be effective in rats with normal or prolonged survival but not in rats with diminished tolerance before stimulation or blockade. An analysis of factors for optimal RES stimulation is presented as are possible mechanisms of action.

Submitted on July 3, 1961
Relation between morphological and physiological events in lung studied by rapid freezing
Authors: Staub Norman C. , Storey Winnifred F.
Published: December 2017

We have applied the method of rapid freezing to the living ventilated lung in the open thorax of cats. Studies in isolated lung lobes showed freezing to depths of 0.1 cm in less than frac12 sec, 0.2 cm in 2 sec. Theoretical calculations based on an idealized model and the experimental data are compared. At these fast rates, ice crystal formation is submicronic and light microscopy shows good histological preservation. We discuss the problem of whether the lung tissues respond to rapid cooling by any detectible alterations of structural form. Indirect evidence from our own and other studies suggests that there is little or no reaction, although further work along this line is necessary. We believe this procedure has important uses as a way to relate structural and functional details within the lung.

Submitted on September 5, 1961
Effect of forward acceleration on renal function
Authors: Watson John F. , Rapp Rita M.
Published: December 2017

The effect of forward acceleration on renal hemodynamics, electrolyte excretion, and water clearance has been studied in six normal human subjects. Forward acceleration produced a slight increase in glomerular filtration rate and effective renal plasma flow during and after stress. After centrifugation there was a 20–35-min lag before the appearance of an increase in urine volume and free water clearance. These changes in water excretion were transient and were not accompanied by a natriuresis nor associated with changes in serum osmolality. Physiologic responses to forward acceleration and negative pressure breathing were compared. It was suggested that forward acceleration, like negative pressure breathing, may induce an increase in intrathoracic blood volume which inhibits the release of antidiuretic hormone via a nonosmotic volume-sensitive receptor mechanism located within the intrathoracic vascular space.

Submitted on September 14, 1961
Diaphragm contraction as a limiting factor to maximum expiration
Authors: Agostoni Emilio , Torri Giorgio
Published: December 2017

Electrical activity of the diaphragm has been studied by means of a bipolar esophageal lead to investigate the high abdominal thoracic pressure difference found at the end of maximum expiration. An esophageal balloon, placed alongside the electrodes and moderately inflated, overcomes the difficulty previously found in using an esophageal lead to study diaphragm activity at small lung volume. At the end of maximum expiration, intense activity of the diaphragm has been recorded. Contraction of the diaphragm at the end of maximum expiration balances the muscle action of the abdominal wall, preventing further reduction of lung volume. Analysis of factors that may set the lower volume limit suggests that contraction of antagonist muscles is the main factor, at least on the abdominal boundary of the thorax. The possible afferent impulses leading to a reflex contraction of the diaphragm at full expiration are discussed.

Submitted on December 18, 1961
Alveolar clearance in dogs after inhalation of an iron 59 oxide aerosol
Authors: Gibb F. R. , Morrow P. E.
Published: December 2017

Six dogs each received two 60-min exposures, 6 months apart, to an aerosol of iron 59 oxide, having an average count median diameter of 0.09 μ and a geometric standard deviation of 1.8. The concentration of iron 59 in the inspired air ranged between 0.004–0.017 μc/liter. Lung measurements were made immediately after each exposure and up to 30 days postexposure. This procedure was followed in both initial and repeat exposures of each dog. A probe-type scintillation detector fitted with a focusing collimator was used to limit the measurements to specific respiratory tract positions on each dog. The biological half-time for alveolar clearance in the 12 studies ranged from 44 to 82 days with an average value of 62 days (sd 8.8 days). This consistency suggests the probability of a normal clearance rate and the possibility of its use as a functional test.

Submitted on July 11, 1961
Nature of sleep in young infants
Authors: Dittrichová J.
Published: December 2017

Using criteria of ocular reactions, bodily activity, and respiration in 12 infants up to 6 months of age, four stages of the waking and the sleeping state have been distinguished: 1) deep sleep, as judged by closed eyes, virtual disappearance of bodily activity, regular respiration, and lowered frequency of breathing; 2) sleep with closed eyes, but greater bodily activity and irregularity of respiration; 3) light sleep, or the transitional state between sleep and waking as manifested by alternating open, closed, and half-open eyes, increased activity and frequency of breathing, and irregularity of respiration; 4) the waking state with open eyes, great bodily activity and respiratory frequency, and irregular respiration. This differentiation has enabled more accurate modification of the usually reported observations concerning the shortening of sleep in early life. It is not the duration of deep sleep which decreases, but rather the transitional state between sleep and waking. The waking state significantly lengthens with age.

Note:

(With the Technical Assistance of V. Lapáccaronková)

Submitted on August 14, 1961
Effect of increased breathing frequency on inspiratory resistance in emphysema
Authors: Channin Elihu , Tyler John
Published: December 2017

The influence of an increase in breathing frequency on the dynamic flow resistance of the lungs has been studied in six patients with pulmonary emphysema. All patients demonstrated the expected fall in pulmonary compliance at the increased breathing rate. In only two of the six subjects did the dynamic flow resistance fall at the increased frequency. The failure to demonstrate the predicted drop in resistance is not due to midposition shifts or to a change in respiratory flow pattern at the higher rate.

Submitted on January 25, 1962
Lactic acid in blood after various combinations of exercise and hypoxia
Authors: Lorentzen F. Vogt
Published: December 2017

Lactic acid was determined in the blood after exercise and hypoxia in various combinations. Seventy-five tests were made on military personnel 20–25 years old. Exercise at a constant work load was done on a bicycle ergometer for 15 min at a chosen simulated altitude. The loads were from 400 to 1,200 kg-m/min and the simulated altitudes were from 10,000 to 17,000 ft. In these experiments on randomly chosen, enlisted Air Force soldiers there was a very great deviation in results, indicating that care must be taken in drawing conclusions about the conditions of stress and altitude from the amount of lactic acid present after an incident.

Submitted on September 12, 1961
Energy and electrolyte metabolism and adrenal responses during work in dogs
Authors: Young D. R. , Price R. , Elder N. E. , Adachi R. R.
Published: December 2017

Studies with dogs were undertaken to determine whether nitrogen metabolism during aerobic treadmill running is affected by recency of food intake. Over a 6-hr period after intake of a standard meal, the percentage of energy derived from carbohydrate, fat, and protein oxidation was relatively constant at 70, 24, and 6, respectively. With postabsorptive dogs, the percentages of energy derived from carbohydrate, fat, and protein were significantly different ( P <.01) and in the ratio of 45:53:2. Urinary nitrogen, amino acids, 17-hydroxycorticosteroids, Na, and K were examined in postabsorptive animals at rest and at work. Over a 3-hr period, the urinary NPN and Na were 0.49 g and 5.8 mEq, respectively, and unaffected by work; K and hydroxycorticosteroids were 4.6 mEq and 228 μg, respectively, and significantly elevated during work. Of 18 amino acids measured, only cystathionine excretion was significantly altered during work. In running trials of 88–600 min duration, both NPN and 17-hydroxycorticosteroids showed a tendency to increase with calorie expenditure.

Submitted on December 22, 1961
Characteristics of an inspiration-augmenting reflex in anesthetized cats
Authors: Reynolds Leslie B.
Published: December 2017

Overinflation or release from deflation of the lungs in anesthetized cats induced a vagally mediated, inspiration-augmenting reflex, characterized by a sudden phrenic motor discharge and an increase in rate and depth of inspiration. It resulted in an increase in end-expiratory volume and lung compliance. In a series of sinusoidal inflations, the reflex could exhibit summation to occur on any single inflation, but having occurred, was temporarily refractory to further inflations. The spontaneous deep breath was shown to be the same reflex, being vagally mediated, and similarly related to changes in mechanical properties of the lungs. The effective stimulus was shown to be a function of velocity and duration of inflation, while the refractoriness shown by the reflex was related to the accompanying increase in end-expiratory volume. The inspiration-augmenting reflex, by increasing functional residual capacity and compliance, was presumed to open alveolar units. It may interact with the Hering-Breuer inspiration-limiting reflex in controlling the respiratory cycle.

Submitted on January 8, 1962
Epileptogenic effects of pure metals implanted in motor cortex of monkeys
Authors: Chusid Joseph G. , Kopeloff Lenore M.
Published: December 2017

The ability of pellets of 26 pure metals to induce clinical epilepsy was evaluated in chronic experiments in 40 monkeys after precentral motor cortical implantation. Nickel and antimony were most effective. A variable mild epileptogenic effect was noted with bismuth, cadmium, zirconium, tin, titanium, iron, molybdenum, mercury, vanadium, tungsten, and tantalum. Other metals, including lead, beryllium, silicon, copper, silver, chromium, cobalt, manganese, zinc, and magnesium were ineffective. Most metal implants were associated with local meningocerebral cicatrix formation, but with five metals (nickel, copper, mercury, antimony, and cadmium) a profound, severe, necrotizing foreign-body reaction occurred. Clinical evidence of toxicity attributable to the metal implants was noted in monkeys treated with nickel, antimony, cadmium, and thallium.

Submitted on February 7, 1962
Effects of dietary protein on physical work capacity during severe cold stress
Authors: Rodahl K. , Horvath S. M. , Birkhead N. C. , Issekutz B.
Published: December 2017

The effect of four different diets ( I: 3,000 kcal, 70 g protein; II: 3,000 kcal, 4 g protein; III: 1,500 kcal, 70 g protein; IV: 1,500 kcal, 4 g protein) on physical work capacity (treadmill running at 7.5 mph and 8.6% grade) was studied in normal young men at ambient temperatures of 22 and 8 C. In 9 days at 22 C there was no difference between the diets with respect to performance capacity. At 8 C no significant deterioration in physical work capacity was observed in nude subjects living on diet I for 9 days, but a marked deterioration occurred after 5 days on diet IV. A significant deterioration also occurred on diet II, as well as on diet III. It is thus evident that a marked reduction in calories or in protein causes deterioration in physical work capacity in men exposed to severe cold stress. In the cold, resting metabolism of men on all diets increased about twofold, resting pulse rate increased by about 20–30 beats/min on an average, and the pulse rate at submaximal work load was similarly increased. There was a significant increase in the urinary excretion of catecholamines in the cold.

Submitted on February 9, 1962
Pulmonary clearance of inert gases with particular reference to ethyl ether
Authors: Noehren Theodore H.
Published: December 2017

Theoretical approaches to inert gas exchange in the lungs have indicated that ventilation, perfusion, and the solubility of the gas (blood-air distribution at equilibrium) are the determining factors in gas elimination by expired air. A mathematical expression is derived to predict clearance of inert gases based on these three factors: Qcl.x = V a.o2Q/(Va.o2 + SxQ). The derivation of this equation is supported by empirical data using ethyl ether in dogs to indicate that the dead space for ether and oxygen are substantially the same under the conditions of this study, and that there is complete equilibration between the ether concentration in arterial blood and end-tidal, “alveolar,” air. The solubility of diethyl ether in blood is high enough that, according to this equation, its pulmonary clearance should be governed by ventilation and substantially independent of cardiac output within ordinary ranges of these two factors. As such, its use as a measure of effective alveolar ventilation in a variety of laboratory and clinical situations is suggested.

Submitted on January 22, 1962
Differences between deep pain responses to hypertonic and hypotonic saline solutions
Authors: Jarvik Murray E. , Wolff B. Berthold
Published: December 2017

Different concentrations of both hypertonic and hypotonic aqueous sodium chloride solutions (0.2 ml) were injected into 24 hypodermic needles inserted in the gluteus medius muscles of 12 human subjects. It was found that a) both duration and intensity of deep pain responses were related to sodium chloride concentration; b) both latency and duration of pain responses were significantly greater with hypertonic than with hypotonic saline solutions; and c) hypertonic saline tended to induce subjective reports of a diffuse, dull ache, whereas hypotonic saline produced descriptions of a sharp, pricking, and well-localized pain.

Submitted on April 3, 1962
Threshold Pco2 dependence on arterial pH for the respiratory system of dogs
Authors: Honda Yoshiyuki , Hasumura Nariko , Natsui Teijiro , Nakamura Keiko
Published: December 2017

By observing respiratory discharges of the phrenic nerve, the threshold values of Pco2 (Ptco2) as chemical stimulus for the respiratory system were examined at varying arterial pH's on anesthetized dogs with and without vagotomy. 1) The reliability of the Ptco2 obtained by this method was high, the standard deviation being 0.48 mm Hg of Pco2. 2) The Ptco2 was lowered as the arterial cH (Ht) was increased by ammonium chloride infusion. The relationship between the Ptco2 and the Ht was linear and the regression line was calculated to be Ptco2 + 0.429 Ht = 44.0 for vagotomized and Ptco2 + 0.361 Ht = 46.1 for nonvagotomized dogs. 3) By combining this equation with that previously obtained expressing the partial effect of increased arterial cH and Pco2 on alveolar ventilation ratio (VR), the general chemical stimulation equation for ventilation in anesthetized normal dogs was derived to be VR = 0.194 Pco2 + 0.071 H – 8.94. 4) The Ptco2 of vagotomized dogs was several millimeters Hg lower than that of nonvagotomized dogs.

Submitted on April 23, 1962
Effect of forward acceleration and negative pressure breathing on pulmonary diffusion
Authors: Zechman Fred , Mueller Gustave
Published: December 2017

Forward acceleration decreases lung volumes, resembling negative pressure breathing (NPB). At 4 g the relaxation pressure curve is shifted downward and to the right 15 mm Hg. Pulmonary gas exchange and diffusion capacity were measured in nine human subjects during NPB (-15 mm Hg) and forward acceleration (4 g). Pulmonary ventilation increased approximately 40% in each condition. The O2 uptake increased with NPB (from 261 to 293 ml/min) and was slightly decreased or unchanged at 4 g. Carbon dioxide elimination increased in both experimental conditions. The apparent steady-state Dco was unchanged by NPB but decreased from an average control value of 21 to 12 ml/min mm Hg at 4 g. Since lung volumes are decreased by comparable amounts in both conditions, it is believed that the deleterious effects observed with forward acceleration are associated with the increased hydrostatic gradient from chest to back.

Note:

(With the Technical Assistance of Justin Taylor)

Submitted on June 4, 1962
Effects of anemia and hemorrhagic shock on pulmonary diffusion in the dog lung
Authors: Burrows Benjamin , Niden Albert H.
Published: December 2017

Hemorrhagic shock induced a marked fall in the pulmonary diffusing capacity for carbon monoxide in the dog (Dl) and produced marked nonuniformity of Dl/Va ratios throughout the lung as assessed by the “equilibration technique”. Difficulties in calculating over-all Dl under these conditions are discussed. Induced anemia also produced a fall in Dl, but little change in the uniformity of Dl/Va ratios was noted. In isolated perfused dog lungs where blood flow, pulmonary vascular pressures, lung volume, and ventilation were maintained constant, Dl was found to be proportional to hematocrit, suggesting either: 1) that virtually all resistance to CO diffusion is in the erythrocyte or 2) that the apparent diffusing capacity of the alveolar-capillary membrane is dependent upon hematocrit, carbon monoxide transfer being reduced across portions of membrane which are some distance from a red blood cell.

Submitted on January 12, 1962
Central and peripheral factors in dynamic thermoregulation
Authors: Randall W. C. , Rawson R. O. , McCook R. D. , Peiss C. N.
Published: December 2017

Direct measurements reveal that hypothalamic temperature is significantly higher than that of the tympanic membrane of the cat under Sernyl anesthesia. The posterior hypothalamus is warmer than the anterior hypothalamus. Bilateral carotid occlusion results in prompt elevation in both anterior and posterior hypothalamic temperatures while the tympanic membrane simultaneously cools. Thus, the hypothalamus is normally cooled by its arterial blood supply while the tympanic membrane is warmed by it. The marked differences in relative temperatures, together with opposite temperature changes imposed by arterial occlusion, underline the danger of assuming identity in temperature of these areas under dynamic conditions. The elicitation of sweating in man by a strong heat stimulus applied to occluded extremities strongly supports the hypothesis that cutaneous thermal receptors participate. The merging of a hot sensation into one of severe pain strongly suggests the participation of the C-fiber system of cutaneous afferents in the response. It is concluded that sweating may be elicited by 1) a primary stimulus arising within the thermal receptors of the anterior hypothalamus, 2) stimulation of cutaneous thermal receptors, or 3) some combination of the two.

Submitted on June 22, 1962
Balance of blood flow and gas exchange during partial heart-lung bypass
Authors: Hopf Max A. , Galletti Pierre M.
Published: December 2017

During partial heart-lung bypass, O2 uptake and CO2 elimination occur simultaneously at two sites: in the natural lung and in an artificial gas-exchange device. The total amount of arterialized blood distributed to the body tissues is the sum of pulmonary blood flow plus extracorporeal flow. When the extracorporeal flow rate is increased, the pulmonary blood flow decreases in proportion, provided the body blood content remains constant. Therefore, the total tissue perfusion during partial heart-lung bypass is not significantly different from the control value. The decrease in pulmonary blood flow is accompanied by a less marked decrease in pulmonary ventilation and gas exchange. Partial heart-lung bypass permits diminishing the pulmonary blood flow while maintaining normal metabolic conditions for the organism.

Submitted on July 24, 1961
A comparison of static volume-pressure relations of excised pulmonary lobes of dogs
Authors: Frank N. R.
Published: December 2017

Comparison was made of essentially static volume-pressure relations of the lobes of excised dogs' lungs during stepwise deflation from a maximal distending pressure of 30 cm H2O. No systematic differences were found among the right apical, middle, and left apical lobes nor between the right and left lungs when gas volume was expressed per unit of tissue weight. However, the right mediastinal-lower and left lower lobes held smaller volumes for any pressure than did the others. The differences were small and appear to play a subordinate role in causing the uneven ventilation typical of healthy lungs. These observations relate only to elastic variations among lobes and are not intended to characterize variations that may exist within lobes.

Note:

(With the Technical Assistance of Eleanor Root)

Submitted on August 13, 1962
Transient responses to CO2 breathing of human subjects awake and asleep
Authors: Fuleihan F. J. D. , Nakada T. , Suero J. T. , Merrifield E. S. , Dutton R. E. , Permutt S. , Riley R. L.
Published: December 2017

Ventilation and end-tidal Pco2 were studied in six subjects awake and asleep (following the ingestion of 200–300 mg sodium pentobarbital) during oxygen breathing and the administration and withdrawal of 4% CO2 in oxygen. During the control period as well as steady-state CO2 breathing, ventilation was significantly lower in asleep than in awake subjects. There was no significant difference between sleep and wakefulness in end-tidal Pco2 or in the slope of the ventilatory response to 4% CO2. The transient responses of ventilation and end-tidal Pco2 of the group as a whole were similar in sleep and wakefulness. Ventilation changed more slowly than did end-tidal Pco2. End-tidal Pco2 overshot beyond the steady-state CO2 breathing value at the onset of CO2 breathing; and undershot below the control value during recovery. The magnitudes of both the overshoot and undershoot of end-tidal Pco2 were correlated significantly to the slope of the ventilatory response to 4% CO2, in the whole group awake and asleep.

Submitted on October 4, 1962