bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of CO2 on hyperventilation produced by vibration
Authors: Young W. A. , Shaw D. B. , Buckles L. J. , Outerbridge J. S. , Reeves C. E. , Truman J. C.
Published: December 2017

Twenty-five normal subjects were exposed to low-frequency high-amplitude passive vibratory movements of the body. Hyperventilation and hypocapnia resulted in most cases. Restoration of the alveolar Pco2 to its resting value by the addition of CO2 to the inspired air while vibration continued gave rise to no further increase in ventilation. It is concluded that the hyperventilation produced by vibration is not moderated by the resulting fall in arterial Pco2. Thus, observed differences between the ventilatory response of different individuals to vibration are unlikely to be due to differences in sensitivity to CO2. Several other studies have demonstrated a threshold level of alveolar CO2 below which respiration is not stimulated by CO2. The lack of response to CO2 in the present experiments may be due to the fact that they have been carried out at levels of alveolar CO2 below this threshold

Submitted on September 21, 1962
Circulatory and ventilatory effects of exercise in smokers and nonsmokers
Authors: Chevalier Robert B. , Bowers John A. , Bondurant Stuart , Ross Joseph C.
Published: December 2017

To evaluate the effects of cigarette smoking on some of the circulatory and ventilatory responses to exercise, a group of young male subjects, 18 smokers and 14 nonsmokers, was studied. Exercise consisted of a standard 5-min bicycle ergometer test that achieved a mean O2 uptake of 1.44 liters/ min in the 5th min of exercise. There was no difference between smokers and nonsmokers in the O2 uptake achieved during subsequent maximal exercise. Pulmonary function studies performed on the two groups revealed normal results for each group. There was an oxygen debt accumulation among smokers that was significantly greater ( P < 0.001) and this debt represented a greater per cent of the total O2 uptake. The heart rate at rest and 3 min after exercise in smokers was significantly faster ( P < 0.02). These differences do not appear to be related to ventilatory factors and may, therefore, be due to either circulatory or metabolic differences in the two groups.

Submitted on August 17, 1962
Differences between ethnic groups in physical working capacity
Authors: Wyndham C. H. , Strydom N. B. , Morrison J. F. , Peter J. , Williams C. G. , Bredell G. A. G. , Joffe A.
Published: December 2017

Maximum oxygen intake per kilogram body weight of Caucasian, Bantu, and Bushmen males in a similar state of physical training are not significantly different, being about 48 ml/min kg. This figure is similar to that of Robinson's Negro sharecroppers and to the U. S. Army recruits of Taylor et al. Very highly trained men, i.e., Åstrand's gymnasts and international class athletes, have higher values. Landy's is 76 ml/min kg. Sedentary existence reduces this figure to about 40 ml/min kg. Oxygen consumption plotted against work rate is significantly lower for Bantu men than for Caucasian; Bushmen are like the Bantu. Ventilation volume (BTPS) plotted against oxygen consumption is about 30 liters/ liter oxygen consumption at 6,000 ft altitude, compared with 20.6 liters for Åstrand's men at sea level.

Submitted on July 1, 1962
Response to high pressure oxygen of conscious volunteers and patients
Authors: Foster C. A. , Churchill-Davidson I.
Published: December 2017

A trial is described in which 19 fit volunteers and 49 patients with malignant tumors have breathed oxygen at a pressure of 3–4 atm abs for periods of from 21 to 67 min in a pressure chamber filled with oxygen. Subjects at complete rest will not safely tolerate 4 atm abs for frac12 hr but are unlikely to show signs of oxygen toxicity in a similar period at 3 atm abs. One patient convulsed during decompression after 46frac14 min at 3 atm pressure. A slow, even rate of pressurization did not prevent the occurrence of otitic barotrauma in nine of the volunteers. The patients had myringotomies performed. Temperature and pulse rate changes are described.

Submitted on May 31, 1962
Volume-pressure relationships during pressure breathing and voluntary relaxation
Authors: Johnson Louis F. , Mead Jere
Published: December 2017

Lung volumes during pressure breathing (PB) were measured in six subjects by two methods: 1) The subject was seated completely enclosed in a body plethysmograph breathing room air through a tube; pressures were applied to this tube and volume changes were recorded from the plethysmograph. 2) The subject was seated enclosed in a body box except for his head which protruded through a respirator collar; pressures were applied around the body and lung volume changes were recorded from a bag-box system. In addition, relaxation pressure (RP) measurements were obtained. Volume-pressure relationships by PB 1 closely approximated those by RP, whereas PB 2 tended to yield smaller volume changes for a given pressure than the other methods. The extrathoracic airways are subjected to the applied pressure in PB 1 and RP, but not in PB 2. The different results may relate to this difference.

Submitted on June 14, 1962
Pulmonary mechanics and diffusing capacity following simulated space flight of 2 weeks duration
Authors: Dubois Arthur B. , Hyde Richard W. , Hendler Edwin
Published: December 2017

Studies of pulmonary mechanics and diffusing capacity were carried out shortly after completion of exposure to the gas composition, barometric pressure, and acceleration profile simulating an earth orbital mission of 2 weeks duration. The values obtained for pulmonary function on the three subjects were normal. However, there still is a potential fire hazard in the atmosphere of 100% oxygen at frac13 atm.

Submitted on January 28, 1963
Optical density changes in dog blood at full oxygen saturation with changes in pCO2
Authors: Salmon Peter , Stish Richard , Visscher Maurice B.
Published: December 2017

Quantitative studies have been made of the changes in optical density of whole blood at two wavelengths at full oxygen saturation with changes in carbon dioxide tension and content. At both λ 630 mμ and λ 805 mμ there are lower densities with increasing pCO2 at full oxygen saturation. From pCO2 1.5 to 243 mm Hg the decrease is 0.133 OD units and is equal at the two wavelengths. The OD is linearly related to the pH change. The effect is ascribed to the differences in light scattering by erythrocytes with changing shape and/or volume of the cells. This effect results in a systematic error in measurements of oxygen content of blood when the carbon dioxide content varies, as it does between arterial and venous blood.

Submitted on October 22, 1962
Relationship between skin temperature and performance in the Java monkey
Authors: Bush Robert D. , Rohles Frederick H. , Reynolds Herbert H. , Koestler Fred G.
Published: December 2017

Four male Java monkeys ( Macaque iris), trained to perform a continuous avoidance task, were used in an exploratory study of diurnal skin-temperature changes and their relationship to avoidance behavior. Significant diurnal skin-temperature changes were detected, and a relationship between bar-pressing rate and skin temperature of the back was shown to exist.

Submitted on December 6, 1962
Effect of vapor pressure on physiologic strain and body heat storage
Authors: Hall John F.
Published: December 2017

Physiologic strain, in terms of body heat storage, and other physiologic responses were measured and compared in two series of heat stress experiments performed on human subjects exposed to different ambient vapor pressures. One group of 75 experiments conducted on 5 healthy nonacclimatized male subjects exposed 5 times each to 38, 54, and 71 C at 10 mm Hg vapor pressure was compared with a series of 81 experiments performed on 10 similar subjects exposed 1–6 times each to 38, 41, and 54 C at 20 mm Hg vapor pressure. Subjects were sitting and wore 1.0 clo insulation. The data show relation between body heat storage and a) the modified Craig index of physiologic strain; b) over-all sweat rate; c) evaporative rate; d) sweat-evaporative ratio; e) mean skin and rectal temperatures; and f) change of heart rate at the respective vapor pressure levels. Statistically significant correlation between sweat-evaporative ratio and over-all sweat rate with body heat storage is shown. Use of the over-all sweat response as a physiologic strain index is suggested.

Submitted on August 14, 1962
Respiratory quotients of human kidney in vivo
Authors: Barker Earl S. , Crosley Archer P. , Clark John K.
Published: December 2017

Renal respiratory quotient (RQ) has been calculated from data collected in unanesthetized human subjects. In contrast to RQ recently reported on anesthetized dogs, these data do not indicate a mean value greater than 1. Under control conditions in 24 subjects, renal RQ calculated without special corrections averaged 0.88. Correcting for differences in blood flow between renal artery and vein due to urine formation the mean was 0.73, with 95% confidence limits 0.49–0.97. With alkaline urines an additional correction for urinary excretion of CO2 is advised. Excluding procedures known to alkalinize the urine, RQ values were similar in 46 observations after a variety of experimental procedures. Since both numerator and denominator of the ratio involve small differences between large values, small analytical errors can produce large changes indistinguishable from physiologic variation. Therefore mean values rather than individual observations are stressed. While such values in our data appear similar to RQ for other organs and the whole body, they do not preclude considerable anaerobic metabolism.

Submitted on August 9, 1962
Regional relationship of water vapor pressure of human body surface
Authors: Ohara Kokichi , Ono Takeo
Published: December 2017

A new simple method for measurement of water discharge from the skin, as well as for estimation of absolute and relative humidity of the skin surface, was reported. The accuracy of the method was high with errors in the order of 2.5%. Estimations were made, using this method, at 108 points over the body of a young healthy nude male subject under neutral thermal conditions. Regional relationship of the rate of insensible perspiration, as well as the absolute and relative humidity of the skin surface, were obtained from the experiments. There was no difference between the regional relationship of the insensible perspiration and that of the absolute humidity. In the regions where perspiration rate is high, the water vapor pressure of the skin surface is also high. Sole, face, palm, and neck are the highest regions. Back of hands and gluteal region are the second highest zone. In distal parts of extremities, there exists an increasing gradient toward the palm or the sole. In the median region of the chest and epigastrium the values are somewhat higher though the chest and abdomen as a whole belong to the lowest regions. Distribution of the relative humidity showed no great difference in general from that of the perspiration rate or absolute humidity. It was found that the regional relationship is not perfectly symmetrical in both sides of the body.

Submitted on January 16, 1963
Application of signal analysis methods to arterial and aortic pressure curves
Authors: Henley Ernest J. , Lukas Daniel S. , Staffin H. Kenneth , Staffin Robert
Published: December 2017

Brachial and aortic cardiovascular pressure waveforms taken from the literature and from New York Hospital patients were subjected to Fourier analysis to determine the harmonic spectrum. The computation, which was performed on a specially constructed analogue computer (Procedyne Associates model 101A) consisted of evaluating the integral (See PDF) The complex transform, F(omega), was analyzed in terms of gain and phase by means of Bode and Nyquist diagrams. The preliminary data show that frequency response techniques may be a useful aid in diagnosing heart disease. In contrast to the normal or mildly defective hearts, the subjects with serious aortic stenosis show pulse waveforms which a) have less high frequency components, b) have no nodes or missing frequencies which are multiples of the fundamental frequency. The paper points to several ways in which advanced signal techniques and control theory can be applied to medical problems.

Bode plot; Fourier transform; harmonic analysis; frequency spectrum; pulse pressure curves; Nyquist diagram; aortic stenosis

Submitted on September 14, 1962
A servomechanism to control output of an artificial ventricle
Authors: Pierce William S. , Burney Robert G. , Williams Kirkley R. , Kirby Charles K.
Published: December 2017

A servomechanism has been designed and built for controlling the output of an artificial ventricle. Venous pressure was selected as the primary parameter of control because of experimental and clinical studies which report this mechanism to assume control under certain conditions in which neural and/or hormonal control mechanisms are attenuated. In this control system, venous pressure, as measured with a pressure transducer, is compared to an “ideal” venous pressure, usually 0 mm Hg. An error signal is thus generated, amplified, and integrated with respect to time. The integrated error signal is fed into a programable d-c power supply. The power supply output runs a small, positive-displacement artificial ventricle. The pump output is controlled by setting the venous pressure. Studies in a mock circulation setup in which venous return was varied over a wide range demonstrated how either blood loss or pooling of blood in the periphery will lead to a diminished ventricular output while the venous pressure is maintained at the same level. This situation has its clinical analogues. It is anticipated that the use of two such venous pressure-controlled artificial ventricles as a heart replacement in the experimental animal will permit changes in heart output in accord with tissue demands both at rest and during exercise.

venous pressure regulation

Submitted on February 28, 1963
Response to cold of Eskimos of the eastern Canadian Arctic
Authors: Brown G. Malcolm , Semple Robert E. , Lennox C. S. , Bird G. S. , Baugh C. W.
Published: December 2017

Skin, muscle, and rectal temperatures, and O2 consumption of Eskimos and Caucasians have been compared during an acute cold exposure involving immersion of one hand and forearm in a 5 C water bath. The Eskimos consumed less O2, maintained their rectal temperatures at a higher level, and gave up less heat from the muscles of the limbs. Though the Eskimos had significantly more adipose tissue, average skin temperatures were the same in the two groups. The pattern of temperatures noted now and the previously observed higher blood flow in the hand and forearm of Eskimos point to increased cooling of arterial blood by returning venous blood in the extremities with resultant preservation of heat in the body core.

Submitted on August 6, 1962
Relationship of radius to pressure along the aorta in living dogs
Authors: Patel Dali J. , De Freitas Flavio M. , Greenfield Joseph C. , Fry Donald L.
Published: December 2017

The instantaneous pressure-radius relationship and mean dimensions were studied at various sites along the aorta in 30 dogs. The pressure-radius relationship was studied in the living state using an electrical caliper to measure the radius continuously through the cardiac cycle. The relative dimensions of the aortic tree at branching sites were calculated from Jeltrate casts made immediately post mortem. The results indicate: 1) The value of ΔR/ΔP and the mean radius decreased with distance along the aorta. 2) The calculated value for Ep, the “pressure-strain elastic modulus” increased monotonically from the ascending aorta to the bifurcation. 3) An “average” arterial tree was constructed from the mean values of the radius obtained from the caliper data and the branching ratios obtained from the casts.

elastic properties, aorta; dimensions, dog aorta

Submitted on March 5, 1963
Respiratory control at high altitude suggesting active transport regulation of CSF pH
Authors: Severinghaus J. W. , Mitchell R. A. , Richardson B. W. , Singer M. M.
Published: December 2017

The role of CSF pH and HCO–3 ion in stimulating respiration was studied in four men during acclimatization from sea level to 3,800 m for 8 days. Mean values for sea level control, 2nd day and 8th day at altitude were, for CSF 7.328, 7.338, and 7.336, and for arterial blood 7.424, 7.485, and 7.484. Ventilatory response to four levels of alveolar CO2 was determined while subjects breathed high oxygen to eliminate peripheral chemoreceptor drive, and for each value of PaCOCO2, arterial and CSF pH were computed. The displacement of the ventilation response curves at altitude from the sea level curves was: -10 mm Hg PaCOCO2, + 0.06 pH unit for arterial blood, but -0.01 for CSF pH. CSF HCO3 was 4–5 mEq/liter lower than control within 1–2 days at altitude, whereas renal buffer base excretion only reduced blood standard bicarbonate 1 mEq/liter after a week. CSF chloride and lactate rose about 6 and 1 mEq/liter. Thus, medullary respiratory chemoreceptor drive, initially reduced at altitude by hyperventilation alkalosis, is restored to normal during acclimatization by reduction in CSF HCO3, the incremental ventilatory drive being supplied by peripheral chemoreceptors. The blood-CSF barrier appears to respond to the initial hyperventilation alkalosis by actively reducing CSF HCO3; the data suggest that CSF pH is thus regulated by active transport by the blood-CSF barrier.

altitude acclimatization; blood brain barrier; regulation of respiration

Submitted on December 17, 1962
Responses of cold-acclimatized men to infused norepinephrine
Authors: Joy Robert J. T.
Published: December 2017

Nine healthy males were infused with norepinephrine (o. μg/kg min) for 20 min before and after five 40-hr weeks of seminude exposure to 5 C. All infusions were given in the basal state, in a quiet room at 27 C, after a 30-min period of control measurements. Rectal temperatures and respiratory rates were unchanged either by the drug or the intervening cold exposure. The drug increased respiratory minute volumes and tidal volumes and decreased heart rates, but equally so in both experiments. Mean skin temperatures were unaffected by the drug but were significantly (P < .025) higher after cold exposure (mean 1 C). Both basal and drug-induced increase above basal of systolic and diastolic blood pressures was significantly lower (P < .025) after cold exposure. Oxygen consumption was the same in both basal periods and was unaffected by the drug before cold exposure. After cold exposure, norepinephrine produced a significant (P < .025) increase in oxygen consumption (mean 18 cc/min m2). These results show a changed sensitivity to norepinephrine in cold-exposed men, with a decrease in vasopressor response and the development of a calorigenic response. The data suggest that in men, norepinephrine may be a mediator of a nonshivering thermogenesis occurring with cold acclimatization.

Note:

(With the Assistance of Joseph C. Matone, Gerald W. Newcomb, and Wendell C. Bradford)

cold exposure; catecholamines; norepinephrine calorigenesis; nonshivering thermogenesis

Submitted on May 2, 1963
Continuous infusion in rats
Authors: Kennan A. L.
Published: December 2017

A simple method of continuous intravascular infusion is described that involves little trauma and is tolerated by pregnant rats. The mechanism is a polyethylene catheter in the tail vein, an accommodating cage in which the rat can move freely, and a mercury U tube to provide pressure for infusion. The method has several advantages in that extensive surgery is not required, the animal can be conditioned to the cage before placement of the catheter, infusion under pressure is possible, and the apparatus is simple and can be set up in any laboratory with equipment at hand.

pregnant rat; catheter; cage

Submitted on May 31, 1963
Binding of calcium by human plasma proteins under simulated physiologic conditions
Authors: Held Irene R. , Freeman Smith
Published: December 2017

The binding of calcium to human plasma albumin, alpha, beta, and gamma globulins was studied with the aid of an ultracentrifuge. The amount of calcium bound to these separated proteins was determined in solutions with electrolyte concentrations and pH within physiological ranges. The total calcium concentration was 2.35–2.90 mm/liter H2O and the total protein concentration was 3.91–4.29 g/100 ml H2O. In these solutions no significant differences were found for the binding of calcium (expressed as mm Ca++ bound per gram protein) by albumin, alpha, and beta globulins; the average values obtained were, respectively, 0.016, 0.018, and 0.023. Significantly less calcium was bound by gamma globulin; 0.009 mm/gram. The pH was varied between 7.200–7.550 and the sodium chloride concentration between 114–157 mEq Na per liter. These changes did not measurably affect the amount of calcium bound to albumin.

protein-bound calcium; ultracentrifugation and determination of protein-bound calcium; plasma globulin-bound calcium; plasma albumin-bound calcium

Submitted on July 2, 1963
Oxytocin effect on myoepithelium of the breast throughout pregnancy
Authors: Wiederman Joseph , Freund Matthew , Stone Martin L.
Published: December 2017

Sensitivity of the myoepithelium of the human breast to oxytocin during gestation has been evaluated in terms of threshold, threshold intensity, threshold lag period, dose response, slope of dose response, and multiple responses. A correlation of these data with advance in gestation was sought. Thresholds, threshold intensities, and threshold lag periods did not vary with age of gestation. Threshold lag periods were inversely proportional to the amplitude of the ensuing response, while amplitude of response was directly proportional to the log of the dose of oxytocin. Slopes of dose response did not vary with gestational age. Spontaneous myoepithelial contractions were found to occur in patients during gestation. Increasing sensitivity (magnitude of response at a given dose) to oxytocin, as found in the uterus, was not evident in the breast during gestation.

myoepithelial contractility; breast during gestation; mammary gland contractile response

Submitted on May 23, 1963
Conduction velocities along course of ulnar nerve
Authors: Schubert Herbert A.
Published: December 2017

The left ulnar nerve was tested on 20 normal subjects on two occasions several weeks apart to determine the motor velocities along various points over the course of the ulnar nerve. Analysis showed that there is no practical difference between proximal and distal motor velocities of the normal ulnar nerve. An approximation of reduced velocity peripheral to the most distal stimulus point can be reflected in the residual latency calculation. Velocity determinations done with stimuli points closer than 10 cm and/or with stimuli at points where the nerve trunk is not superficial are subject to considerable error.

residual latency; motor velocity of ulnar nerve; axonostenosis

Submitted on October 15, 1963
Plasma free fatty acids in exercise
Authors: Rodahl K. , Miller H. I. , Issekutz B.
Published: December 2017

The effects of exercise of different intensity and duration on plasma free fatty acids (FFA), blood glucose, and lactate were investigated in eight healthy young men. In heavy 10-min work the blood lactate rose rapidly and the FFA decreased. Blood sugar showed no marked change. Intermittent work caused a slight increase in blood lactate and no change in blood glucose. The FFA remained essentially unchanged but increased in three out of four subjects during recovery. In moderate 1-hr work the FFA remained essentially unchanged, but increased markedly during recovery when blood lactate had returned to resting levels. In prolonged exhausting work in fasting subjects, the blood lactate remained almost unchanged, while the FFA rose steadily and the blood sugar dropped. In nonfasting subjects the FFA also rose, but the ingestion of lunch caused, in all cases, a striking drop in the FFA, associated with a rise in blood sugar. Combined hormonal effects (insulin and norepinephrine) brought into play during exercise of different intensity and duration may well explain the apparent discrepancy in the results of different investigators concerning the effect of exercise on plasma FFA.

work and FFA; FFA at different workloads; lipid metabolism in work

Submitted on November 6, 1963
Physiological reactions to cold of men in the Antarctic
Authors: Wyndham C. H. , Plotkin R. , Munro A.
Published: December 2017

The physiological reactions to cold of five members of the 1961–1962 South African expedition to the Antarctic were studied in a climatic chamber in Johannesburg, and again after 6 months and after 12 months in the Antarctic. Their results were compared with the results of a control group in Johannesburg. The predeparture results were within the 95% significance intervals of the control group. After 12 months in the Antarctic their results fell outside the 95% significance intervals of the control group when at 5 C air temperature, metabolism, average skin temperatures, rectal temperatures, and finger temperatures were all significantly lower. Toe temperatures, however, were higher. There appeared to be a gradual “adaptation” and general “toughening” to the cold, because the subjects shed their clothing progressively until they could run about naked in the snow. The values at the thermoneutral zone of 27 C did not change over the 12 months, however. It is therefore concluded that it is unlikely that the changes in physiological responses were of endocrine origin.

cold adaptation in Antarctic; metabolic and body temperature reactions to cold

Submitted on August 16, 1963
Balance and kinetics of anaerobic energy release during strenuous exercise in man
Authors: Margaria R. , Cerretelli P. , Mangili F.
Published: December 2017

The speed of lactic acid formation in blood has been measured in man as a function of the intensity of exercise and was found to reach a maximum of about 36 mg lactic acid/liter blood per sec, corresponding to about 21.5 kcal (kg hr) or 0.034 hp/kg. The maximal energy release sustained by the alactacid mechanism is of the order of 45 kcal/(kg hr), or 0.07 hp/kg. The alactacid debt, as measured in man running on a treadmill, seems to be approximately proportional to the energy expenditure: it amounts at most to 0.1 kcal/kg or about 1.4 liters O2 for a man weighing 70 kg. The lactacid debt amounts at most to 0.22 kcal/kg or about 3 liters O2 for man, on the average. The alactacid oxygen debt contraction is a faster process and it requires 10–30 sec for completion, while the lactacid debt process is completed in about 40 sec in the most strenous exercise. Therefore, at the highest workloads, the only energy source available after 40 sec resides in oxidative processes.

oxygen debt; lactic acid

Submitted on July 5, 1963
Functional adaptation to rigorous training and exercise in diabetic and nondiabetic adolescents
Authors: Larsson Yngve , Persson Bengt , Sterky Göran , Thorén Claes
Published: December 2017

Functional adaptation to training and exercise was studied in six diabetic and six nondiabetic boys, 15–19 years of age. The training program consisted of 5 months' regular physical activity with stepwise increasing intensity. At the end of this period the subjects took part in a cross-country ski run, lasting for 3–4 hr and repeated on 3 consecutive days. Exercise tests were made at regular intervals with both submaximal and maximal workloads and work capacity was expressed as maximal oxygen uptake (max Vo2). At the beginning of the study the diabetic boys had lower functional capacity than the controls, but during training the max Vo2 as well as heart volume increased similarly and significantly in both groups. At submaximal workload the lactate concentration was the same among the diabetics as in nondiabetics, but at exhaustion it was somewhat lower in the former group. The caloric intake increased substantially (ca. 50%) in all subjects but during the actual work hours the carbohydrate intake was greater among the diabetics than among the controls. Glycosuria in the diabetic group was approximately unchanged during the whole study. All subjects could fulfil the work, and there were no untoward effects of exhaustion. In the diabetic group insufficient caloric supply and the concomitant risk of hypoglycemia seemed to be the most important limiting factor for prolonged heavy work, but the responses and adaptation of pulmonary and cardiovascular functions were adequate and similar in both groups.

juvenile diabetes; prolonged exercise; exercise tests; maximal oxygen uptake; blood lactate; caloric intake

Submitted on October 23, 1963
Etherőair anesthesia for small experimental animals
Authors: Walker F. W.
Published: December 2017

An apparatus using compressed air for the semiquantitative administration of ether-air mixtures to experimental animals has been constructed in quantity from bottles, polyethylene tubing, and roller clamps available from hospital discard. Ether concentrations at various flow rates can be derived from the depression of the partial pressure of oxygen in the ether-air mixture. Inexpensive and useful in research, the apparatus also acquaints the student with the quantitative aspects of inhalation anesthesia.

anesthetic apparatus for experimental animals; ether vapor concentration calculated from pO2 in ether-air mixtures

Submitted on June 10, 1963
Chart viewer
Authors: Lentini E. A. , Guyton W. V.
Published: December 2017

An inexpensive chart viewer was constructed to facilitate analyses of oscillographic records obtained through the use of the electronic micrometer. The viewer was designed to meet the criteria of economy, compactness, measuring versatility, simple electrical design, variable speed control, and smooth operation. A variety of oscillographic records can be analyzed by using this instrument. It is easy to operate and structurally sturdy.

oscillographic record analyzer; mechanical viewer; electrical chart roller

Submitted on February 27, 1964
Reduction of retroactive effects of interpolated maze training in hypothermic mice
Authors: Essman Walter B. , Sudak Frederick N.
Published: December 2017

In two experiments the retroactive effect of maze training interpolated between an initial acquisition phase and a testing phase was determined in mice. In the first experiment a retroactive inhibitory effect was demonstrated in animals given interpolated training for the reversal of an acquired maze response. In the second experiment the interpolated activity was either habit reversal, overtraining, or practice swimming. When the interpolated activity was initiated in the presence of hypothermia habit reversal did not occur, no retroactive inhibition was shown, and facilitation of performance from overtraining or practice swimming was negated. The data support the hypothesis that hypothermia maintained during maze training reduces the negative (retroactive inhibition) as well as positive (facilitation) effects that such training has upon the performance of a previously acquired maze habit.

maze learning in mice; maze acquisition during hypothermia; hypothermia and interpolated maze training; animal behavior; learning in hypothermic animals; hypothermia and maze acquisition

Submitted on January 16, 1964
Collateral ventilation in excised dog lungs
Authors: Nakamura T. , Takishima T. , Takasugi R. , Sasaki T.
Published: December 2017

Lobes of excised dog lungs were cannulated so that all segmental bronchi were connected to one of two cannulae. When one cannula was obstructed all ventilation beyond the point of obstruction was through collateral passages. Changes in effective lobar compliance with cycle duration, and changes in the lobar spirograms following abrupt changes in translobar pressure were interpreted in terms of underlying changes in collateral flow. In lobes from six dogs collateral flow was not detected in two and showed marked individual variations in the other four. It decreased relative to total lobar flow when the duration of the imposed volume cycle was decreased, and it increased when the degree of lobar inflation was increased. The latter finding suggested associated increases in the size of the stomata between adjoining alveoli.

effective lobar compliance; stomata

Submitted on September 11, 1963
Flow rate of erythrocytes in the capillaries of the lung
Authors: Schlosser Dieter , Heyse Ernst , Bartels Heinz
Published: December 2017

The rate of blood flow in the capillaries of the rabbit lung was investigated by cinematographic methods and found to be 0.75 mm/sec during artificial respiration with air applied with a Starling pump during the filming. Using our measured value for the average capillary length of 68 μ, the average contact time for the erythrocytes is 0.1 sec. If we assume the capillaries to have a length of 100 μ, the contact time would amount to 0.15 ± 0.05 sec. The discrepancy with the saturation time obtained from in vitro experiments is discussed. It is shown that insufflation increases the capillary blood flow in the lungs.

blood flow; velocity; rabbit; microcinematography

Submitted on February 24, 1964
Evidence for adrenal insufficiency in acutely stressed captive monkeys
Authors: Nagle Jack P. , Cammock Earl E. , Nyhus Lloyd M. , Harkins Henry N.
Published: December 2017

A number of postoperative complications in Macaca nemestrina suggested possible adrenal insufficiency secondary to chronic stress. Adrenal function was assessed by use of plasma 17-hydroxycorticoids, total eosinophil counts, and ACTH-response tests. Surgery or anesthesia resulted in a rise in plasma 17-hydroxycorticoids and a fall in total eosinophils in the majority of monkeys, and all of these animals demonstrated at least a 50% decrease in the total eosinophil count 4 hr following the intramuscular administration of ACTH. However, in three monkeys this type of response did not occur following one or both of the tests that were done. These three animals, unlike the others, presented one or more of the following complications during the poststress period: lethargy, failure to eat properly, diarrhea, and diuresis. These findings indicate that the stress of captivity may deplete adrenal reserve and alter normal physiological responses.

primates (Macaca nemestrina); primates, adrenal reserve in primates, total eosinophil counts; primates, corticosteroid levels; adrenal reserve, evaluation of adrenal function, postoperative; captivity, adrenal exhaustion in

Submitted on October 21, 1964
Dynamic accuracy of the electromagnetic flowmeter
Authors: O'Rourke M. F.
Published: December 2017

Dynamic calibration of electromagnetic flowmeters was performed by resolving the output signal when sinusoidal flow of known characteristics was pumped through the probe. In two instruments amplitude and phase were found to be frequency dependent in the range 0–20 cycle/sec; the magnitude of these effects was not insignificant as many have assumed. In a sine wave instrument using a variety of probes, both amplitude and phase increased linearly with frequency: the former increasing by 0.57% per cycle per second, the latter by 3.6° per cycle per second. In the square wave flowmeter at 0 damping, amplitude decreased significantly above 5 cycle/sec, while phase lag increased by 4.9° per cycle per second. These effects are concluded to be due to the output filtering network. In the sine wave instrument it was demonstrated that magnetic field nonuniformity within the probe did not alter the accuracy in recording steady or oscillatory flow. It was thus possible to construct a small short flowmeter probe having narrow electromagnet coils, and it is expected that this probe should cause minimal interference to pulsatile flow patterns.

magnetic fields flowmeter probes; frequency-response flowmeter

Submitted on April 16, 1964
Role of skin and of core temperatures in man's temperature regulation
Authors: Wyndham C. H.
Published: December 2017

The response characteristics have been studied of the curves relating heat conductance and sweat rate to change in rectal temperature at different levels of skin temperature, and vice versa. The increase in these responses with deviation in rectal temperature from the “neutral” setting is highly nonlinear; the neutral point and the curve shift to the right and the slope decreases with lowering of skin temperature and vice versa when it is raised. With further deviation of rectal temperature these responses reach maximum values, i.e., become “saturated.” All of these features are analogous to servomechanisms with negative feedback, giving sensitive and stable control. Control of these responses by skin temperature is more linear, characterizing passive control systems which are insensitive and less stable. Quantitatively, the effect at skin temperature of 26 C of 1 C rise in rectal temperature on heat conductance and sweat rate is 10 times greater than the same rise in skin temperature; at a neutral skin temperature of 33–34 C, a rise of 1 C in rectal temperature is 6–7 times greater; at a high skin temperature of 36 C, a rise in rectal temperature of 1 C is 4–5 times greater.

relationship between heat conductance and a change in either rectal or skin temperatures; relationship between sweat rate and a change in either rectal or skin temperatures; response characteristics of curves relating heat conductance to change in either rectal or skin temperatures; response characteristics of curves relating sweat rate to change in either rectal or skin temperatures; assessment of the contribution of skin and rectal temperatures to man's temperature regulation

Submitted on October 22, 1963
Pulmonary hypertension with muscular exercise in the newborn calf
Authors: Reeves John T. , Leathers James E.
Published: December 2017

Two types of pulmonary hypertension occur with muscular exercise (walking) in the calf on the day of birth: a) Pulmonary arterial pressure increased in all calves during exercise. The increase was greatest in the youngest calves. Pulmonary arterial pressures did not rise to systemic levels and arterial oxygen saturations remained normal. Pulmonary hypertension subsided in 2 min after stopping exercise. Pulmonary arterial pressure rose again when exercise was repeated. Both an increased pulmonary flow and pulmonary vasoconstriction may have contributed to the increased pulmonary arterial pressure during exercise. b) Pulmonary hypertension was observed in five calves for 30-50 min after exercise ceased. When pulmonary arterial pressure exceeded aortic pressure, arterial oxygen unsaturation occurred. This pulmonary hypertension which occurred only once per calf resembled"spontaneous" pulmonary vasoconstriction observed in resting calves on the day of birth. It is postulated that some substance remaining in the lung after fetal life, rather than the acutely reduced oxygenation of mixed venous blood, initiated this pressor response.

hypoxia; pulmonary vasoconstriction

Submitted on May 11, 1964
An analysis of the mechanics of phonation
Authors: Cavagna G. A. , Margaria R.
Published: December 2017

The mechanical work done by the chest in phonation has been measured together with the sound intensity level. The regulation of the sound intensity is done by regulating the intrapulmonary pressure. This is achieved at high intensity levels through the activity of the respiratory muscles that, together with the elastic recoil of the chest, sustain the work of phonation. At sound intensities below a critical level an additional mechanism for changing the intensity is given by a fine regulation of the opening of the glottis, thus allowing more air to escape without contributing to sound production. The contribution of the respiratory muscles, of the chest elasticity, and of the opening of the glottis to phonation at different intensity levels depend on the degree of inflation of the chest. The efficiency of phonation, as of sound production in mechanical models, seems to increase with increasing intensity and pitch.

voice production; work done by chest during phonation; mechanical models of glottis generator; subglottic pressure as a function of sound level; air flow through glottis during phonation; efficiency changes of sound production; variation of sound intensity by regulating opening of glottis; variations of the area of glottis depending on extent of elastic recoil of chest

Submitted on February 10, 1964
Indwelling catheters for small bats
Authors: Kanthor Harold A.
Published: December 2017

Techniques are described for preparation and use of polyethylene small-animal catheters for 7-g bats.

Urine collection, small animals; catheters, small animals; polyethylene catheters

Submitted on August 6, 1964
Precise control of stimulation parameters in low impedance conditions
Authors: Mills L. W. , Swett J. E.
Published: December 2017

A system is described for accurate control of stimulation parameters in conditions where impedances between 100 and 30,000 ohms are encountered across the secondary of a stimulus isolation transformer. The dual-channel stimulator is constructed mainly from Tektronix 160 series pulse and waveform generators. The stimulator was designed primarily for evoked potential studies in the nervous system with peripheral nerve stimulation but will operate equally well with concentric or needle electrodes in deep brain structure, providing that total electrode-tissue impedances are kept within the stipulated limits. The unique feature of the stimulator is embodied in the operational amplifier interposed between the Tektronix stimulus pulse generator and the primary of the isolation transformer. This system is designed to read directly in stimulus intensities relative to any stipulated physiological threshold. Absolute stimulus voltages may be continuously monitored to ± 3% accuracy. The impedance matching characteristics of the described system will permit effective stimulation of excitable tissues while maintaining stimulus control by the operational amplifier settings within ± 1%. The large range of pulse durations, stimulus intensities, and the use of more than one type of stimulus waveform, have been sacrificed in favor of maintaining rigid control over pulse waveforms and amplitudes with passage of large stimulating currents at low intensities. This system comes close to achieving those qualities embodied in the ideal constant voltage stimulator.

physiological stimulation; biological stimulator; low impedance stimulation; Tektronix-adapted units for biological stimulation; isolated stimulator; nerve stimulator; physiological threshold stimulator

Submitted on July 10, 1964
A photopotentiometric transducer for detecting in vitro muscle contractions
Authors: McIntosh Max , Duggan Dennis E. , Watt Dean D. , Goodson Louis H.
Published: December 2017

In vitro muscle contractions can be detected and recorded by using a light-sensitive solid-state potentiometer as a transducer. The amount of light reaching the photosensitive potentiometer is controlled by movement of a shield across the potentiometer in response to muscular contractions. The apparatus is relatively frictionless, sensitive, inexpensive, and needs little or no amplification when the signal is transmitted to ordinary recorders.

photosensitive solid-state potentiometer; frictionless transducer; Schultz-Dale reaction; hypersensitivity; anaphylaxis

Submitted on August 10, 1964
Influence of a tranquilizer on temperature regulation in man
Authors: Iampietro P. F. , Fiorica V. , Dille R. , Higgins E. A. , Funkhouser G. , Moses R.
Published: December 2017

The effects of a tranquilizing drug of the propanediol group, meprobamate, on thermal balance of men exposed to a cold (50 F, 10 C), hot (110 F, 43.3 C), or neutral (80 F, 26.7 C) environment have been investigated. Results show that a single dose of meprobamate (800 mg) has no effect on temperature regulation of men resting in a neutral environment. During exposure to hot or cold environments, however, the drug groups showed impairment in thermal balance. In the cold, heat production and core temperature of the drug group were lower than those of the placebo group. In the heat, only moderate elevations in the core temperatures of the drug group were detected. Possible physiological mechanisms responsible for these differences are discussed.

human exposure to heat and cold; drugs and temperature regulation; catecholamines in heat and cold; meprobamate; heat; cold

Submitted on October 9, 1964
Temperature regulation and cold acclimation in the golden hamster
Authors: Pohl Hermann
Published: December 2017

Characteristics of cold acclimation in the golden hamster, Mesocricetus auratus, were 1) higher metabolic rate at -30 C, 2) less shivering when related to ambient temperature or oxygen consumption, and 3) higher differences in body temperature between cardiac area and thoracic subcutaneous tissues at all ambient temperatures tested, indicating changes in tissue insulation. Cold-acclimated hamsters also showed a rise in temperature of the cardiac area when ambient temperature was below 15 C. Changes in heat distribution in cold-acclimated hamsters suggest higher blood flow and heat production in the thoracic part of the body in the cold. The thermal conductance through the thoracic and lumbar muscle areas, however, did not change notably with lowering ambient temperature. Marked differences in thermoregulatory response to cold after cold acclimation were found between two species, the golden hamster and the thirteen-lined ground squirrel, showing greater ability to regulate body temperature in the cold in hamsters.

hibernator; oxygen consumption— heat production; body temperature — heat conductance; muscular activity — shivering; thermoregulation

Submitted on July 6, 1964
Comparison of maximal oxygen uptake values determined by predicted and actual methods
Authors: Glassford R. G. , Baycroft G. H. Y. , Sedgwick A. W. , Macnab R. B. J.
Published: December 2017

Twenty-four male subjects aged 17–33 were given three direct tests of maximal oxygen uptake and one indirect test. The direct tests were those of Mitchell, Sproule, and Chapman (treadmill); Taylor, Buskirk, and Henschel (treadmill); and Åstrand (bicycle ergometer). The indirect test was the Åstrand-Ryhming nomogram (bicycle ergometer) employing heart rate response to submaximal work. In addition, the Johnson, Brouha, and Darling physical fitness test was administered. The two treadmill tests and the indirect test yielded significantly higher mean values than did the direct bicycle test. However no other significant differences in mean values occurred. Correlation coefficients between the various oxygen uptake tests as well as the fitness test were all found to be significant (.62–.83), i.e., greater than zero. No correlation obtained proved to be significantly greater than any other. The results indicate that direct treadmill tests, employing greater muscle mass, yield higher maximal oxygen uptake values (8%) than does the direct bicycle ergometer test. The Åstrand-Ryhming nomogram appears to produce a good estimation of maximal oxygen uptake, in a population unaccustomed to cycling.

erobic capacity; exercise; heart rate

Submitted on September 17, 1964