bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of basolateral potassium conductance by taurine in the proximal convoluted tubule
Authors: Breton S. , Belachgar F. , Marsolais M. , Lapointe J. Y. , Laprade R.
Published: December 2017

The effect of taurine on the electrophysiological properties of the basolateral membrane of the rabbit proximal convoluted tubule was examined. Short-duration isosmotic pulses of 40 mM taurine in the bath solution induced basolateral membrane depolarizations (delta Vbl) of 6.44 +/- 0.5 mV, which were reduced by 58% in absence of Na+. In presence of barium and quinine, delta Vbl values were reduced by 55% in Na(+)-containing bath solutions and were completely abolished in Na(+)-free solutions. Continuous addition of taurine into the bath solutions for a period of 5 min induced 1) a decrease in the partial conductance of the basolateral membrane to K+ (tK) from 0.39 to 0.23; 2) an increase in the partial conductance to Cl- (tcl) from 0.055 to 0.172; 3) a rapid and transient increase of the partial conductance mediated by the Na-HCO3 cotransporter (tNaHCO3) from 0.37 to 0.52, followed by a progressive decrease to 0.29; and 4) a depolarization of the basolateral membrane of 16 mV. The absolute membrane conductance mediated by the Na-HCO3 cotransporter was not initially affected by taurine, whereas that to K (GK) initially decreased by a maximal factor of 2 after 1 min, followed by a partial recovery after 5 min, and that to Cl (GCl) increased by a factor of 4. Addition of taurine after a hypotonicity-induced cell swelling produced an inhibition of GK comparable to the one observed under isotonic conditions. These results demonstrate the presence of an electrogenic Na-dependent transport of taurine and indicate that taurine inhibits GK.
Functional evidence for a Ca2+/polyvalent cation sensor in the mouse thick ascending limb
Authors: Paulais M. , Baudouin-Legros M. , Teulon J.
Published: December 2017

The effects of extracellular polyvalent cations on the cytosolic free Ca2+ concentration ([Ca2+]i) of isolated segments of the mouse nephron were investigated using fura 2 microfluorometry. Extracellular Ca2+ concentration ([Ca2+]o), gadolinium (Gd3+), and neomycin (Neo) increased the [Ca2+]i in cortical thick ascending limb (CTAL) tubules with effective doses (ED50) of approximately 3.5 mM for Ca2+, 20 microM for Gd3+, and 40 microM for Neo. This effect was reproduced by Ba2+ but not by Mg2+. High [Ca2+]o inhibited the responses to Gd3+, Neo, and Ba2+. The Gd(3+)- and Neo-evoked [Ca2+]i transients persisted in the absence of external Ca2+ and were abolished by the depletion of internal Ca2+ stores with thapsigargin (TG). The responses to rises in [Ca2+]o were similarly inhibited by TG and slightly reduced by 20 microM La3+ but not by 10 microM nifedipine. Mn2+ also mobilized a TG-sensitive internal Ca2+ store and stimulated its own entry. External Ca2+, Gd3+, and Neo induced small but significant increases in [Ca2+]i in distal convoluted tubule, cortical collecting duct, and outer medullary collecting duct segments, transiently increased [Ca2+]i in some medullary TAL (MTAL) tubules, but had no effect on descending thin limb. We conclude that a Ca(2+)-mobilizing Ca2+/polyvalent cation sensor resembling that of the parathyroid gland cells is predominantly located in the mouse CTAL but also in the MTAL and, to a lesser extent, in more distal segments.
Regulation of Na channels in the rat cortical collecting tubule: effects of cAMP and methyl donors
Authors: Frindt G. , Palmer L. G.
Published: December 2017

The whole cell patch-clamp technique was used to investigate the interactions of the amiloride-sensitive Na channel of the rat cortical collecting tubule (CCT) with adenosine 3',5'-cyclic monophosphate (cAMP) and with methyl donors. The amiloride-sensitive whole cell current (INa) was measured in principal cells of dissected, split-open tubules from rats maintained either on a control diet or on a low-Na diet to increase endogenous aldosterone secretion. With Na-depleted animals, INa was highest immediately after rupture of the membrane patch and averaged 325 pA at a membrane potential of -60 mV. INa declined over 15 min to approximately 35% of the initial value. With 8-(4-chlorophenylthio)-cAMP in the pipette, INa increased within 5 min of membrane rupture and was maintained for 15 min at levels three- to fourfold higher than the corresponding control values. With Na-replete animals, INa was undetectable (< 10 pA) without cAMP. With cAMP in the pipette, INa averaged 40 pA. In cell-attached patches on tubules from Na-replete rats exposed to cAMP, single Na channels were observed with conductive and kinetic properties similar to those from Na-depleted rats but at lower density. Inclusion of the methyl donor S-adenosyl methionine to the pipette solution did not increase INa in CCTs from Na-replete rats, either in the presence or absence of cAMP. The methylation inhibitor S-adenosyl homocysteine did not affect INa in CCT from Na-depleted animals.
Oxygen cost of voluntary hyperventilation
Authors: Murray John F.
Published: December 2017

The oxygen cost of voluntary hyperventilation was measured using an open circuit technique with three variations, unaided hyperventilation of air, breathing through an increased dead space and adding carbon dioxide to the inspired air. After a given minute volume had been maintained for 10 minutes, the oxygen consumption was the same with the three methods, in spite of marked differences in the respiratory exchange ratio and volume of carbon dioxide produced. The mean oxygen cost for all three methods was 3.2 ml/l. of ventilation. The amount of nonmetabolic oxygen stored during the first minute of hyperventilation was estimated by finding the difference between the oxygen uptake during the 1st minute and the amount utilized when a steady state is reached. It is concluded that the effects of changing oxygen stores are minimal after 10 minutes of hyperventilation and probably after 5 minutes, at a constant minute volume.

Note:

(With the Technical Assistance of Liana Nebel)

Submitted on June 27, 1958
Withdrawal of peripheral lymph from the foot of the dog
Authors: Silk Michael H. , Mears Arthur R. R.
Published: December 2017

Peripheral lymph was withdrawn simultaneously from an untreated foot and an x-irradiated foot of anesthetized, healthy dogs. Previous techniques were modified to give large yields of sterile, clot-free lymph. A method is described for addition of anticoagulant solutions at a controlled rate during lymph withdrawal. The pentobarbitone (Sagatal, May Baker) anesthetic content of peripheral lymph was shown to be not greater than 0.05 mg/ml. The protein content of peripheral lymph withdrawn 3 hours after 450 r x-irradiation of the paw was found to be not significantly different from that of normal peripheral dog lymph

Submitted on March 11, 1958
Estimation of inspiratory capacity in health and in subjects with respiratory muscle paralysis
Authors: Spencer William A. , Vallbona Carlos
Published: December 2017

A method is described for the reproduction of the natural inspiratory capacity in healthy subjects utilizing a pressure breathing device capable of delivering high inflow rates at low pressures (1.3 l/sec. at 5 cm of water in the delivery system). A highly significant correlation was found between natural inspiratory capacity and the estimation of inspiratory capacity carried out in this manner in healthy subjects. The reliability of this method in cooperative individuals suggested applicability in patients with respiratory muscle paralysis when maximum natural inspiration is impossible. In poliomyelitis subjects with respiratory muscle paralysis the values of estimated inspiratory capacity were significantly reduced below those found in health. The degree of reduction was not directly related to the diminution of natural inspiratory capacity or to the maximum volume changes that could be produced by means of tank respirator assistance at comparable peak transthoracic pressures. Measurement of inspiratory capacity with this technique together with the determination of functional residual capacity makes it practical to estimate the total lung capacity and thus describe the lung compartments in such subjects.

Submitted on June 10, 1958
Some effects of carbon dioxide on foreign gas uptake
Authors: Shephard Roy J.
Published: December 2017

Partitional respirometry in normal subjects breathing 1-5% CO2 indicates a large increase of alveolar dead space, but in the steady state there is no consistent change of diffusing capacity or effective pulmonary blood flow. An apparent early decrease of diffusing capacity is probably an artefact due to difficulties in measuring acetylene uptake with a changing respiratory minute volume, and if Dco is measured by the breath-holding technique, carbon dioxide produces no immediate effect. Hypercapnic hyperventilation does not help in making acetylene uptake conform to a single exponential curve. The ventilatory efficiency indicated by partitional respirometry in a nonuniform system is dependent on both solubility of the test gases and the mean Va/Q ratio. An analogue computer for the solution of Va/Q problems is described.

Submitted on August 18, 1958
Tolerance to acute anoxia in high altitude natives
Authors: Velásquez Tulio
Published: December 2017

Native residents living at an altitude of 14,900 feet were suddenly exposed to simulated higher altitudes, ranging from 30 to 40,000 feet, in a low pressure chamber. The ‘time of consciousness’ and the ceiling breathing air were determined. In addition, observations were made on the respiratory characteristics at these altitudes. Comparing the results with those given by previous investigators using sea level residents, they indicate that a man born and living at an altitude of 14,900 feet has a definitely greater tolerance to acute hypoxia than a man born and residing at sea level. The relative influence of hypoxia and hypocapnia on the symptoms which developed during this test is discussed.

Note:

(With the Technical Assistance of Edgard Florentini and Melquiades Huayna-Vera)

Submitted on June 2, 1958
ŅFree roamingņ in the albino rat and its effect on restraint hypothermia
Authors: Bartlett R. G. , Young M. W.
Published: December 2017

‘Adaptation’ to a large environment increased the resistance of young adult female (175–225 gm) Sprague-Dawley rats to restraint hypothermia. Two changes may have occurred in the ‘free roaming’ rats which rendered them less susceptible to restraint hypothermia: 1) emotional adaptation to the changing stimuli of the ‘free roaming’ state may have lessened the emotional stress produced by restraint which would have reduced the hypothermic response ( Am. J. Physiol. 79: 343, 1954), 2) a possible cross-resistance produced by adaptation to the nonspecific stresses involved in the ‘free roaming’ state which would have inhibited restraint induced hypothermia ( J. Appl. Physiol. 8: 661, 1956).

Submitted on September 8, 1958
Measurement of rates of excretion of sweat solutes under physiological conditions
Authors: Barrueto Richard B. , Mager Milton , Bass David E.
Published: December 2017

An apparatus is described which permits the study of rates of excretion of sweat solutes under physiological conditions from an arm, and which permits regulation of skin temperature of the arm independent of ambient conditions. The apparatus permits the collection from the arm of all sweat solutes separately from the associated water. This is accomplished by isolating an arm in a thermoregulated copper cylinder. Air is circulated through the cylinder and the sweat water is collected in a trap system; the solutes are subsequently washed from the arm and the washings are analyzed. It was shown that the rates of excretion of sodium, potassium, chloride, ‘apparent’ creatinine and urea were the same from an arm enclosed in the apparatus as from the unenclosed arm. Thus, the apparatus can be valid44ly used in studying the effects of various environments on sweat gland activity for the five substances measured.

Submitted on July 31, 1958
Maximal heart rate during work in older men
Authors: Åstrand Irma , Åstrand Per-Olof , Rodahl Kaare
Published: December 2017

Nine 56–68-year-old male subjects performed muscular work up to maximal loads on a bicycle ergometer while breathing both ambient air and oxygen. Heart rate increased to an average maximum of 163/min. The maximal O2 intake averaged 2.24 l/min. and the blood lactic acid concentration 85 mg/100 ml. In no case was the maximal heart rate higher when breathing O2 than when breathing air. This low maximal heart rate in older people probably limits the capacity for O2 intake. Four subjects were able to work for about 1 hour without any sign of exhaustion on a work load requiring an O2 consumption of about 50% of their maximal aerobic work capacity.

Submitted on October 3, 1958
Viscous metamorphosis, clot retraction and other morphologic alterations of blood platelets
Authors: Zucker Marjorie B. , Borrelli Jennie
Published: December 2017

Some samples of washed platelets undergo viscous metamorphosis (VM) in oxalated or citrated plasma, oxalated serum or serum poor in prothrombin. Other samples only undergo VM when serum containing residual prothrombin is used and thrombin is evolved when platelets are added. Thrombin produces VM at pH 7.4 but not at pH 6.1 or in isotonic saline. Treatment of thrombin with diisopropylfluorophosphate (DFP) or addition of heparin plus serum inhibits VM. Spreading of platelets upon glass, and balloon formation are not closely correlated with VM. Clot retraction in a purified system often occurs without added buffer or glucose, but is always very marked in the presence of both buffer and glucose. Calcium binding anticoagulants prevent VM and clot retraction. The inhibition is reversed by calcium and, to a lesser extent, magnesium. Cyanide (4 or 5 x 10-3 m) does not inhibit VM or retraction in a purified system but inhibits retraction of platelet-rich plasma, especially when it is clotted with thrombin. At this concentration, fluoride has a variable effect. Mercuric chloride is an effective inhibitor of both VM and retraction at concentrations of 10-4 m and below.

Submitted on November 20, 1958
Survival of rats and mice without oxygen in deep hypothermia
Authors: Adolph E. F. , Goldstein J.
Published: December 2017

Adult rats and mice that were cooled quickly below 11℃ core temperature usually ceased to breathe. Suspension of breathing and heartbeats was tolerated at 2℃ for 1 hour, whether artificial breathing was given or not and whether air or nitrogen filled the lungs. At heart temperatures of 10℃, where heart beat was maintained, rats survived artificial ventilation with nitrogen for 0.4 hour; ventilation with air for 2 hours. Anaerobic survival at 10℃ was not demonstrably shortened by inhibitors of glycolysis (fluoride, iodoacetate). Reanimation of 90% of rats and mice under optimal conditions was accomplished by artificial warming, accompanied by artificial ventilation with air under intermittent positive pressure. Each process that becomes suspended at its biological zero apparently has a limited time within which rewarming may restore it. The limitation of times less than 1.5 hours was imposed mostly by anoxia. Properties of animals that were injured by anoxia or by hypothermia seemed to vary, since animals might die even after breathing was restored.

Submitted on January 12, 1959
Energy metabolism in laboratory workers
Authors: Banerjee Sachchidananda , Sen Rabindra Nath , Acharya Keshav Narayan
Published: December 2017

Energy expenditure during different activities of 11 laboratory workers was determined by measurement of oxygen consumption. The energy cost of various activities expressed as Calories per m2 body surface per hour were as follows: BMR 30.87 ± 0.741; lying rest 34.79 ± 0.578; sitting rest 36.61 ± 2.927; standing rest 41.24 ± 1.323; sitting study 42.85 ± 1.034; sitting work 46.79 ± 3.036; standing laboratory work 59.96 ± 3.937; standing household work 61.78 ± 3.675; walking 122.06 ± 6.25; ascending stairs 159.94 ± 5.610 and descending stairs 95.80 ± 6.3. The total daily energy expenditure of the subjects, determined for a period of 7 days, varied between 1620 and 2967 Cal. The average food actually consumed by the subjects was analyzed for fat, protein and carbohydrate to determine the calorific value. The intake varied between 1680 and 2928 Cal/day. Most of the subjects were in apparent positive caloric balance but caloric intake was probably overestimated becauseno correction was made for the caloric value of the excreta.

Submitted on October 21, 1958
Food distribution during mastication
Authors: Askew Harold C.
Published: December 2017

Roentgenologic observation of food distribution during mastication was made for 61 subjects wearing full artificial dentures. Thirty-one subjects (51%) displayed a predominantly unilateral food distribution, 22 subjects (37%) a simulataneous bilateral distribution, 5 subjects (8%) showed an equal utilization of the above two distribution methods, and 2 subjects (3%) showed the food distribution either between the upper and lower anterior teeth or in the center of the mouth. Essentially the same results were obtained with 12 subjects examined both by static x-ray pictures and fluoroscopy.

Submitted on February 2, 1959
Effect of mechanical factors on respiratory work and ventilatory responses to CO2
Authors: Eldridge Frederic , Davis John M.
Published: December 2017

The end-tidal pCo2, mechanical work of breathing, and ventilation were determined in normal subjects breathing air, 2.2, 4.2 and 5.8 per cent Co2, with no added resistance and with three grades of added airway resistance. With increasing resistance, pCo2 and work rose in parallel whereas ventilation remained constant or even decreased. In the presence of a constant Co2 stimulus, increasing airway resistance caused a progressive decrease in ventilatory response to Co2. The maximum breathing capacity was not in itself the limiting factor in the ventilatory response to Co2. It is concluded that mechanical abnormalities of the respiratory apparatus are an important factor in reducing the ventilatory response to Co2, and that work of breathing is a more satisfactory index of respiratory stimulation than ventilation. Since patients with obstructive emphysema have nonelastic resistance values in the same range as those used in this study, it is concluded that the low ventilatory response to Co2 in these patients can, in large part, be explained by the mechanical abnormalities.

Submitted on April 28, 1959
Energy metabolism and gas exchange during treadmill running in dogs
Authors: Young D. R. , Mosher R. , Erve P. , Spector H.
Published: December 2017

The energy cost of treadmill running was studied in six dogs at grades of 0, 4, 8, 12, 16, 19 and 22 degrees of inclination. The relationship between caloric expenditure and grade is significant. A product-moment coefficient of correlation of +0.978 was found. A product-moment coefficient correlation of +0.941 was found between work pulse rate and caloric expenditure. Climbing efficiency showed a maximum of 28% and decreased at the lowest and highest grades. Respiratory efficiencies were highest during resting conditions. Maximum O2 uptake increased with age to a peak value of 136 cc/kg/min. at 1 year of age. Maximum 24-minute recovery O2 debts of 4–6 liters were measured following exhaustive running. The data form a basic standardization background for application of the treadmill as a device for studies of controlled work output in the dog.

Submitted on September 17, 1958
Effect of tolbutamide on glucose uptake by leucocytes of patients with diabetes mellitus
Authors: Dumm Mary E.
Published: December 2017

Glucose uptake and lactate production have been measured in suspensions of leucocytes in plasma. The rate of glucose uptake of the leucocytes of diabetics who required less than 30 u of insulin per day did not differ significantly from that of normal subjects and was higher than that of severe diabetics. Two hours after 1 gm of tolbutamide was given intravenously to the diabetic subjects, glucose uptake and lactate production tended to increase in subjects whose blood sugar fell at least 12%. Glucose uptake and lactate production by the leucocytes increased in some, but not in all normal subjects after the oral administration of glucose. Observations on the effects of tolbutamide are compatible with the hypothesis that one effect of the drug is to enhance the secretion of insulin by the pancreas.

Submitted on May 28, 1959
Metabolic studies on perinatal human brain
Authors: Himwich Williamina A. , Benaron Harry B. W. , Tucker Beatrice E. , Babuna Cevat , Stripe Margaret C.
Published: December 2017

Oxygen consumption and carbon dioxide production were determined on minced samples of cerebral cortex, caudate nucleus, thalamus and medulla oblongata of the brains of 22 human infants ranging in age from 160 to 283 days of gestation. A significant correlation of age and oxygen consumption was obtained for cerebral cortex, caudate nucleus and thalamus. The oxygen consumption of these parts was greater than that of the medulla oblongata after 200 days of gestation age. The results emphasize the impossibility of comparing the brain of the neonatal human being with the young of other species until more comparative developmental data are available.

Submitted on April 30, 1959
Uptake of cyclopropane by the human body
Authors: Sechzer P. H. , Dripps R. D. , Price H. L.
Published: December 2017

The uptake of cyclopropane was measured in 5 human subjects who breathed a 1% concentration of the gas in oxygen for periods ranging from 7 to 62 minutes. The measured concentrations of cyclopropane in end-expired air were compared with those predicted by Kety's equation ( Pharmacol. Rev. 3:1, 1951) describing the saturation process for inert gases. Although fair agreement was found between the measured and predicted data, it was noted that the measured values increased more rapidly than theory predicted. This difference apparently resulted from Kety's simplifying assumption that the body consists of a homogeneous tissue mass.

Submitted on May 25, 1959
Tolerance and cross-tolerance development to atmospheric pollutants ketene and ozone
Authors: Mendenhall R. M. , Stokinger H. E.
Published: December 2017

Tolerance to oxidants, that is remarkable both in its rapidity of onset and its high degree of protectiveness, has been demonstrated in mice exposed briefly to ketene. Exposure of mice to concentrations of ketene in excess of 5 ppm for 10 minutes protected mice 3–14 days later against otherwise lethal exposures. Similarly, a cross-tolerance was demonstrated for ozone; a pre-exposure to ketene protected mice against lethal concentrations of ozone. Ozone likewise produced a cross-tolerance for lethal exposures to ketene. The 10-day LC50, which is the concentration required to produce a 50% kill in 10 days by a 10-minute exposure of mice to ketene, approximates 17 ppm (v/v), with production of pulmonary edema. Pulmonary edema of lesser degrees resulted at lower exposure concentrations, but was not present to a significant extent in mice exposed to lethal concentrations of the respiratory oxidants, provided the mice had first received a tolerance-producing pre-exposure of the respiratory oxidant.

Submitted on June 8, 1959
A modified Harvard step test for women
Authors: Sloan A. W.
Published: December 2017

The fitness indexes of two groups of healthy young women performing the Harvard step test on steps of various heights were compared with the fitness indexes of a corresponding group of men performing the test on a step of the standard height (20 inches). The closest agreement with the results of the men was attained by women using a step 17 inches high. Not only did the mean fitness indexes correspond, but also the distribution of individuals in the several categories of physical fitness.

Submitted on June 15, 1959
Adrenolytic and sympatholytic action of certain dihydrogenated ergot alkaloids (Hydergine) on dog kidney
Authors: Kubicek W. G.
Published: December 2017

Adrenolytic action of dihydrogenated (DH) ergot alkaloids was estimated in denervated dog kidneys and the sympatholytic action was estimated on electrically stimulated renal nerves. Blood sugar level, hematocrit, blood pressure and pulse rate were observed in most of the experiments. The minimal effective intravenous dose of Hydergine or its components to block the epinephrine vasoconstriction in the denervated kidneys was approximately 3.5 μg/kg of body weight while a somewhat larger dose was required to block sympathetic nerve impulse transmission. Oral administration of these alkaloids required a dosage approximately ten times the minimal effective intravenous dose. The DH ergot alkaloids reduced the epinephrine-induced hypertension and had little if any effect upon the hyperglycemia and elevated hematocrit observed during continuous epinephrine infusions.

Submitted on May 29, 1959
Lung volumes of singers
Authors: Heller Stanley S. , Hicks William R. , Root Walter S.
Published: December 2017

Lung volume determinations (tidal volume, inspiratory capacity, inspiratory reserve volume, expiratory reserve volume, vital capacity, maximum breathing capacity, functional residual capacity, residual volume, and total lung capacity) were carried out on 16 professional singers and 21 subjects who had had no professional vocal training. No differences were found between the two groups of subjects, whether recumbent or standing, which could not be explained upon the basis of age, size, or errors involved in making the measurements.

Submitted on March 24, 1959
Effect of breathing O2 at one atmosphere on O2 consumption of rats
Authors: Froese Gerd
Published: December 2017

The O2 consumptions of different groups of rats, young, old, warm acclimatized and cold acclimatized, were compared in atmospheres of O2 vs. air at different temperatures. Significant effects of O2 were found in some cases, not in others, and even the direction of change was different. In spite of the diversity of the results, plotting the O2 consumption breathing air minus that breathing air vs. the level of O2 consumption gave significant negative correlations. The O2 effect therefore exists, but depends on the level of metabolism. The effect was shown to be transient, lasting up to 3O minutes. It could not be attributed to changes in the amount of gases dissolved in body fluids of the rats. It probably represents a transient effect on a steady-state metabolic system and might be thought of as a first sign of ‘ O2 poisoning.‘

Submitted on January 20, 1959
Reflections in model and arterial pulse waves
Authors: Evans Robert L. , Hosie Kenneth F. , Kooiker Robert H. , Perry John , Stish Richard J.
Published: December 2017

Intermittent half-sine wave flows were used to introduce pressure pulses into a distensible tube model. These pressure pulses were measured and were analyzed quantitatively for their forward-propagated and retrograde components, assuming that the components have the same propagation velocity in their respective directions. An arterial pulse showing relatively much reflection was analyzed similarly for comparison and was found to have a reflected component no greater than three-tenths as much as the propagated component, which is considerably less than the reflections occurring in the model.

Submitted on February 27, 1959
Changes in foot volume and capillary fragility during continuous cold exposure and starvation
Authors: Norman Paul S. , Kreider Marlin B. , Iampietro P. F.
Published: December 2017

The effects of continuous cold exposure (2 wk. at 60°F) and starvation on foot volume and capillary fragility were studied in six men. The experimental period was preceded and followed by 2-week periods (control and recovery) at 80°F and a caloric intake of 2400 cal. Foot volumes decreased 6.1% in the first 5 hours of cold exposure and remained constant for the remainder of the experimental period. Foot volume was also measured after 3 minutes of elevation of the foot and occlusion of the blood supply. This volume decreased less during the experimental than the preceding or following periods. Capillary fragility decreased slowly during the experimental period and increased in the recovery period. On the third day of recovery, foot volumes were larger than at any other time. For the remainder of recovery, foot volume was the same as the control volume, but there was a greater decrease in volume with foot elevation. The results suggest that there was a constriction of all types of blood vessels during the experimental period while in the recovery period there was apparently a simultaneous dilatation of large blood vessels and a constriction of small ones. One subject had a greatly increased volume of one foot associated with pain and redness during early recovery days. These changes may be indicative of early trench foot or capillary damage. Starvation per se appeared to have no effect on foot volume.

Submitted on October 15, 1959
Effect of negative intra-alveolar pressure on pulmonary diffusing capacity
Authors: Cotes J. E. , Snidal D. P. , Shepard R. H.
Published: December 2017

In one of two subjects studied in detail, using 0.1% carbon monoxide in the test gas and a 10-second breath-holding period, the alveolar capillary blood volume (Vc) was found to increase by nearly 100% when the intra-alveolar pressure was made negative during breath holding. This was accompanied by a reduction in venous pressure in the forearm. In both subjects Vc was increased on exercise. The diffusing capacity of the alveolar capillary membrane (Dm) remained relatively constant in spite of large changes in Vc. The findings suggest that stationary blood is present in some alveolar capillaries at rest. The implications of this finding and a likely mechanism for the increase in Vc with negative pressure are discussed.

xsSubmitted on September 14, 1959
Effect of hypothermia on ventilatory response to carbon dioxide inhalation and carbon dioxide infusion in dogs
Authors: Salzano John , Hall F. G.
Published: December 2017

Some respiratory and circulatory responses to carbon dioxide stress during ice-water immersion hypothermia were studied in 13 dogs. Stresses were imposed by increasing the carbon dioxide tension of the inspired gas in eight animals and by intravenous infusion of gaseous carbon dioxide in five other animals. It was found that when compensation is made for the depressed ventilation exhibited at low body temperature, animals responded to the carbon dioxide stresses in essentially the same manner in the hypothermic as in the normothermia state. However, the responses are of a lower order of magnitude.

Submitted on November 19, 1959
Effects of local cooling or heating in deeply hypothermic rats
Authors: Orchard D. P. , Adolph E. F.
Published: December 2017

Rats were cooled to 17°C core temperature, and then either the head or the chest was further cooled by 5° – 10°. Thermocouples in the hypothalamus and in the vena cava recorded the differences of temperature; electrocardiograms and breathing were observed. Breathing could cease reversibly when the head was cooled and also after a period of gasping whenever the heart was much cooler than the head. Artificial ventilation of the lungs with air did not modify the result of restricted blood flow. Whenever the brain was cooler than the heart, however, artificial ventilation with air could replace spontaneous breathing; the blood flow was then usually adequate. Artificial ventilation with nitrogen reduced the time within which recovery was possible. In general the warmest tissue (head or chest) determined the time of endurance without adequate delivery of oxygen from lungs and blood. Any local cooling failed to increase the rat's endurance of oxygen lack. The results are interpreted to mean that failures to survive below 14°C for 1 hour are due to inadequate oxygen delivery. However, even oxygen delivery believed to be adequate did not allow indefinite survival; 2 hours remained the mean tolerance time below 14°C.

Submitted on November 23, 1959
Physiological studies during hypothermia in monkeys
Authors: Bryce-Smith R. , Epstein H. G. , Glees P.
Published: December 2017

Rhesus monkeys were subjected to hypothermia (20°C) after initial, light anesthesia. Heart rate, EEG and minute volumes during spontaneous respiration were recorded. With cooling there was a progressive fall in heart rate, respiratory rate and minute volume unrelated to the type of anesthetic agent (quantitatively administered ether or i.v. pentobarbitone). Spontaneous EEG waves disappeared at 23°C following initial anesthesia with pentobarbitone, but persisted to 19°C after ether anesthesia. Bemegride injected into the hypothermic monkeys caused activation of the EEG. It is concluded that similar procedures could be applied with safety to human subjects for psychiatric purposes.

Submitted on August 28, 1959
Lung volumes, lung compliance and airway resistance during negative-pressure breathing
Authors: Ting E. Y. , Hong S. K. , Rahn H.
Published: December 2017

Lung volumes, airflow resistance and lung elastance were measured in seven subjects during various degrees of continuous negative-pressure breathing in the supine posture. At –30 cm H2O the expiratory reserve is reduced to about 30% of its normal value and the resistance to airflow is more than doubled. On the other hand, the pressure-volume curve of the lung measured with the aid of an esophageal balloon was not significantly altered by either negative-pressure or positive-pressure breathing.

Submitted on February 8, 1960
Ventilatory mechanics and strength: long-term re-examinations and position change
Authors: Brody Alfred W. , O'Halloran Patrick S. , Wander Harry J. , Connolly John J. , Roley Everett E. , Kobold Elmer
Published: December 2017

Sixteen comparisons (3 in females, 13 in males) were made of pulmonary function tests in the standing, seated and supine positions. The significant changes were an increase in tidal volume on standing from either the seated or supine positions, but no change on lying (supine) from the seated position; a progressive decrease in the expiratory reserve volume on going from the standing to the seated to the supine positions; an increase in the inspiratory capacity on lying supine from either seated or standing positions, but no significant change on standing from the seated position; and a suggestion of increased turbulence (k2 term) on passing from the seated to either of the other positions. The other functions tested (minute volume, vital capacity, maximal pressures, elastance, resistance, maximal flows) did not change significantly. The variation and progression of week-to-week changes are described for five paralyzed patients after poliomyelitis and three normal subjects studied over a 2–3 month period. The changes occurring in five normal subjects studied at about 9-month intervals for periods of 9–39 months are also described.

Submitted on August 17, 1959
Influence of unilateral hypoxia on blood flow through the lungs in man in lateral position
Authors: Arborelius M. , Lundin G. , Svanberg L. , Defares J. G.
Published: December 2017

The relative blood flow through the separated lungs was determined with six subjects in lateral position. The amount of CO2 eliminated from each lung and the end-tidal air composition gave the necessary data to determine the relative flow through each lung, at assumed total blood flows through both lungs of 3, 6 and 12 liters. The lower lung was allowed to breath 10% oxygen in nitrogen and the upper lung air. The values obtained at all the above mentioned total blood flows were about the same, and also did not show any difference from the values obtained when both lungs were breathing 30% oxygen in nitrogen. In the last case the relative blood flow is assumed to be the same as the relative oxygen uptake for each lung. Hypoxia on the lower lung thus does not cause any shift to the air-breathing lung. This is in contrast to earlier experiments, performed by the authors, with the subject in supine position. Using the same measuring technique, it was then found that hypoxia on one lung caused a large shift of blood to the air-breathing lung.

Submitted on February 1, 1960
Maximal work production in man
Authors: Fletcher J. G.
Published: December 2017

The ability to perform hard physical work was studied quantitatively in 12 well-motivated men who undertook to step up and down a 22-inch bench 30 times every minute until exhausted. By this procedure a 150–lb. man performs external work at a rate of 0.25 h.p. or 1140 kg-m/min. When first tested, nonathletes were not able to step as long as athletes, inactive subjects as long as active ones, or athletes out of training as long as those in full training. Seven subjects exercised repeatedly. All found that their endurance increased by 100% or more. In five of them the improvement exceeded 500%. Reductions in pulse rate, at rest and after standard periods of stepping, accompanied the training process.

Submitted on December 7, 1959
Alveolar-arterial oxygen gradient in the dog at altitude
Authors: Kreuzer F. , Tenney S. M. , Andresen D. C. , Schreiner B. F. , Nye R. E. , Mithoefer J. C. , Valtin H. , Naitove A.
Published: December 2017

The effect of a sojourn of 5 days at an altitude of 14,300 feet (White Mountain, Cal.) on the alveolar-arterial oxygen gradient (A-aDo2) in the anesthetized dog was studied at three levels of oxygenation. Two dogs breathed 11% o2, air and 100% o2 at sea level, and air, 40%, and 100% o2 at altitude, with ventilation kept constant by means of a respiration pump. The alveolar samples were analyzed for o2 and CO2 pressures with the Scholander apparatus and the arterial o2 pressures were measured in an in vitro polarograph. Control studies showed that the pump itself and hyperventilation had no effect on the A-aDo2. The average values of A-aDO2, 8.6, 23.4 and 168.5 mm Hg, at sea level (the three values refer to the respective three levels of oxygenation; the last figure corresponds to a shunt of about 12% of cardiac output) agreed well with previous data. The corresponding average values of A-aDO2 at altitude were: 3.3, 17.0 and 58.0 mm Hg (corresponding to a shunt of about 4%). The A-aDO2 breathing air was lower at altitude than when breathing an equivalent oxygen tension at sea level. The most dramatic effect consisted in a threefold decrease of the A-aDO2 with 100% O2 at altitude, indicating a decrease in true veno-arterial shunt flow.

Submitted on February 8, 1960
Relationship of carotid pressure and end point during acceleration
Authors: Kydd George H. , Fenichel Richard L. , Crosbie Richard J.
Published: December 2017

Simultaneous observations have been made of the occurrence of an end point of unconsciousness and carotid blood pressure in rhesus monkeys during positive acceleration. The data indicate that the carotid pressure is influenced initially by a maneuver which gives rise to a positive wave of pressure that is well coordinated with the onset of tangential acceleration, while positive acceleration is at a very low level. Following this, there is a pressure drop that can be described by a time constant, that is, a function of peak g. The data indicate that the end point occurs after a constant interval following the pressure minimum and is therefore related to the slope of the blood pressure curve. The significance of this observation with respect to blood supply is discussed.

Submitted on March 14, 1960
Relation of olfactory acuity to nasal membrane function
Authors: Schneider Robert A. , Wolf Stewart
Published: December 2017

The relationship between olfactory perception threshold and accompanying degrees of nasal obstruction, swelling, color and wetness was studied in eight subjects over a prolonged period. Olfactory acuity was impaired in two situations: a) in the presence of high degrees of nasal obstruction so that relatively little of the odorant-containing air could be brought into the nose, and b) in the absence of obstruction when the mucosa was relatively pale, dry and shrunken. During intermediate degrees of nasal obstruction when substantial amounts of air could be drawn into the nose relatively high degrees of swelling, redness and wetness favored olfactory acuity. Thus smelling was best performed in the presence of a red, swollen, wet mucosa as long as swelling and secretions were not of such a degree as to substantially block air passage. The evidence suggests that contact of odorant with nerve endings is facilitated by the greater warmth and humidifying effect of nasal engorgement during hyperfunction of the ‘air-conditioning’ apparatus of the nose.

Submitted on March 14, 1960
Method for kinetic study of in vitro conversion of a C14-labeled substrate to CO2
Authors: Allweis Cecil L. , Gainer Harold , Chaikoff I. L.
Published: December 2017

A method is described for the determination of CO2 and C14O2 production rates by tissue slices incubated in the presence of a constant concentration and constant specific activity of a C14-labeled substrate. The constant conditions were maintained by periodic replacement of the incubation medium and gas phase. It is pointed out that, in order to determine the true rates of conversion to CO2 of an exogenous labeled substrate and of an endogenous, nonequilibrating CO2 precursor, measurements must be made after isotopic equilibration is attained. In the case of whole brain slices, such equilibration was observed after 3–4 hours of incubation. With glucose as the exogenous substrate, 30–40% of the CO2 produced by rat whole cerebrum slices was derived from endogenous sources for as long as 12 hours.

Submitted on December 14, 1959
Suggested methods of testing and standards of resistance for respiratory protective devices
Authors: Cooper E. A.
Published: December 2017

There is need to establish a method of bench testing and standards of allowable resistance for respiratory protective devices. It is suggested that a technique for recording pressure-volume diagrams using a sine-wave pump is satisfactory. Standards of resistance are proposed which are expressed as total rate of respiratory work done on the apparatus, and the percentage of this which is done in expiration. It is suggested that apparatus should be tested at minute volumes up to 100 l/min. Other information derivable by this technique is discussed. Fundamental principles of aerodynamics are also considered in relation to closed-circuit breathing apparatus. It is shown that under conditions of practical use of such systems, flow is only laminar in rare instances. Useful information can be gained about the frictional resistance of a respiratory circuit from simple bench tests at various constant rates of flow of air, and from the results of such experiments theoretical calculations can be made of the rate of work done. They are shown to correspond well with the measured rates of work done by human volunteers when breathing against the same resistance at all levels of exertion on a treadmill.

Submitted on March 7,1960
An improved heart-lung preparation ventilated by negative pressure
Authors: Sheehan William L. , Kinzie William B. , Westbrook Kenneth L. , Spencer William A. , Hoff Hebbel E.
Published: December 2017

Five isolated canine heart-lung preparations were successfully ventilated with intermittent negative pressure in a specially constructed chamber. Improved cardiopulmonary dynamics resulted in increased survival time and improved performance of all preparations. Results obtained with these preparations exceed most of the others reported in the literature.

Submitted on May 9, 1960
Seasonal acclimatization to cold in man
Authors: Davis Thomas R. A. , Johnston D. R.
Published: December 2017

Six subjects were measured once monthly from October to February for alterations in shivering, heat production, and rectal and skin temperatures produced by a standard cold exposure of 14.1 α 0.46°C for 1 hour. The responses of a second group of five subjects were measured once monthly from February to September during a cold exposure of 13.7 α 0.9°C. In the October-February group, shivering decreased to a January mean value 7% of the October figure ( P < 0.01). Cold-induced heat production decreased in February to a value 52% of the October figure ( P < 0.05). Mean rectal temperature and mean surface temperature over the total period of study showed no consistently significant change. The decrease in shivering was associated with a change in the surface temperature threshold of shivering onset. The February-September group showed an increase in shivering reaching a maximum in September ( P < 0.01). Again consistently significant alteration in surface or rectal temperature could not be demonstrated. The highly significant change in shivering and the less significant change in heat production observed suggests that man seasonally acclimatizes to cold and that this acquired acclimatization is lost during the summer months.

Note:

(With the Technical Assistance of F. C. Bell, W. Rawlings and L. Lee)

Submitted on May 27, 1960
Evaluation of venous occlusion plethysmograph
Authors: Conrad Margaret C. , Green Harold D.
Published: December 2017

Inflow and outflow, occlusion and perfusion pressures, and pressure in a small vein in the paw were measured simultaneously with the plethysmogram on the amputated forepaws of dogs. Venous tamponade was complete for a period of time dependent on the height of occlusion pressure and the magnitude of arterial flow. Paw venous pressure rose rapidly to 'effective occlusion pressure,' at which time blood began to escape beneath the occlusion cuff. Arterial flow began to decline immediately after occlusion. Two occlusion artifacts were observed. The first was an abrupt deflection that could be easily avoided on the plethysmogram, and the second was a slower rise that could be detected only when inflow was interrupted prior to occlusion. The plethysmographically measured flow was not significantly different from inflow measured with the electromagnetic flowmeter because of a balance between the positive error due to artifact and the negative error due to the effect of occlusion on inflow.

Submitted on September 22, 1960
Aortic mechanics in the living dog
Authors: Patel Dali J. , Mallos Alexander J. , Fry Donald L.
Published: December 2017

The relationship between longitudinal strain, circumferential strain, lateral intravascular pressure, blood velocity, and longitudinal motion was examined in the aortas of 25 living thoracotomized dogs. Electrical calipers with adequate recording characteristics were used for instantaneous measurement of diameter and length. The results indicate: a) with inspiration, the thoracic aorta increased in length and the abdominal aorta shortened. b) During cardiac systole the length in the thoracic aorta increased with a rise in pressure, mean value for longitudinal extensibility x 103 was 15% (α 4.8 S.D., α 1.1 S.E.M.) per centimeter H2O pulse pressure. The mean value for the ratio of circumferential extensibility to longitudinal extensibility was 10. c) The abdominal aorta shortened with cardiac systole. This shortening is thought to be produced by elongating strain of the thoracic aorta. d) The absolute magnitude of aortic wall velocities, both radial and longitudinal, was very small as compared to the blood velocity at the same site.

Submitted on August 18, 1960