bluuebunny/crossref_metadata_2025_split huggingface dataset:
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