bluuebunny/crossref_metadata_2025_split huggingface dataset:
Somatic afferent activity in reflex regulation of diaphragmatic function in the cat
Authors: Sant'Ambrogio Giuseppe , Wilson Michael F. , Frazier Donald T. 
Published: December 2017

Experiments were performed to disclose the functional role of afferent activity from the diaphragm, previously described as proprioceptive. Electromyographs were recorded by leads placed in the diaphragm of anesthetized and decerebrate cats. The experiments indicate that in basal conditions interruption of the afferent connections from the diaphragm (i.e., section of the appropriate dorsal roots) did not change the electromyographic activity of the diaphragm. Even during maneuvers known to increase the afferent discharges from the diaphragm, such as negative pressure breathing and abdominal compression, division of the afferent inflow failed to cause a consistent change in the electromyographic patterns of the diaphragm activity. The vagal reflexes from the lungs (Hering-Breuer) remained the same with and without somatic deafferentation. Electrical stimulation of the cervical roots constantly evoked a polysynaptic response recorded either from the diaphragm or the phrenic nerves. This reflex response, without a monosynaptic component, cannot represent a potential myotatic reflex mechanism. The results of these experiments indicate an absence of proprioceptive drive in the reflex regulation of diaphragmatic function. Submitted on December 7, 1961
Influence of vagal blockade on respiratory and circulatory functions in hypothermic dogs
Authors: Salzano John , Hall F. G. 
Published: December 2017

Anatomical and physiological dead spaces were enlarged as a result of reduction in body temperature to 28 C in spontaneously respiring anesthetized dogs. Respiratory dead space at 32 C was not significantly different from that at normal body temperature. Vagal blockade resulted in an increase in tidal volume and decrease in respiratory frequency and increased anatomic and physiologic dead space at normal and reduced temperatures. Alveolar ventilation and cardiac output declined equally (percentagewise) with reduction in body temperature to 32 C; at 28 C alveolar ventilation fell more precipitously so that alveolar ventilation-cardiac output ratio (ventilation-perfusion) at 28 C was approximately one-half that at 37 and 32 C. Arterial-alveolar carbon dioxide pressure differences were independent of temperature and vagal blockade. The results indicate no impairment of gas transport or gas exchange at 32 or 28 C in spontaneously respiring anesthetized dogs. Submitted on January 11, 1962
Measurement errors in estimating aortic blood velocity by pressure gradient
Authors: Greenfield Joseph C. , Fry Donald L. 
Published: December 2017

The computed pressure-gradient technique is important in measuring instantaneous blood flow and velocity in man. Estimation of the instantaneous pressure gradient for this purpose presents many special problems. This study was designed to explore these special measurement problems and to establish certain minimum pressure-recording standards for application of the computed pressure-gradient technique to man. The nature of the functions to be measured was first explored by determining average values and harmonic content of typical pressure, flow, and pressure-gradient curves. In contrast to pressure and flow curves, the harmonic content of pressure-gradient curves was found to exceed the recording capabilities of currently available systems for measuring differential pressure. However, when velocity was computed from pressure gradient, the importance of errors related to higher frequencies is greatly diminished. To meet minimum requirements differential-pressure catheter-manometer systems should have a dynamic imbalance of less than 5% through frequencies of 15 cycles/sec, a single-ended dynamic response uniform (±5%) through 15 cycles/sec, and a static imbalance not greater than ±0.1% over the range 0–300 cm H2O. Although an optimum pressure tap separation could not be precisely defined, visual examination suggested that a tap separation of 8 cm should not be exceeded. Submitted on April 30, 1962
Alveolar CO2 during breath holding and exercise
Authors: Craig Albert B. , Babcock Stuart A. 
Published: December 2017

When 12 healthy adult male subjects held their breath after breathing 100% O2, the PaCOCO2, at the breaking point was higher when they exercised than when they were at rest. Attention was not a factor, and passive exercise did not produce a result different from rest. By repeated breath-holding experiments at different work loads it was possible to demonstrate a systematic error due to the sampling site, the alveolar air. When this error was examined quantitatively, it was found that there is probably no difference in the Pco2 at some critical sensing site at the breaking point under the different conditions of voluntary apnea. Our results imply that exercise may not change the sensitivity to CO2, or at least the sensitivity is not decreased. Submitted on March 16, 1962
Regional differences in gas exchange in the lung of erect man
Authors: West J. B. 
Published: December 2017

Measurements of regional ventilation and blood flow using radioactive CO2 show that both increase from apex to base of the lung; the results are used to build an integrated picture of gas exchange. Ventilation-perfusion ratios at nine levels of the lung have been calculated and differences in local gas exchange deduced. In the resulting model, alveolar O2 tension changes by more than 40 mm Hg from apex to base while CO2 and N2 tensions change by about 14 and 29 mm Hg, respectively. Maximal differences in O2 saturation of end-capillary blood are 4% but differences in CO2 contents of 7 vol % and pH variations of 0.12 units occur. The O2 uptake per unit lung volume increases eightfold down the lung while corresponding variations in CO2 output are less than threefold. N2 passes out of the blood in upper parts of the lung but into the blood in basal regions (net exchange is zero). Over-all O2 uptake and CO2 outputs are reduced by only 2–3% by the ventilation-perfusion ratio inequality, causing alveolar-arterial differences of 4, 1, and 3 mm Hg for O2, CO2, and N2, respectively. Submitted on April 6, 1962
Changes in serum enzyme levels after exercise in trained and untrained subjects
Authors: Fowler William M. , Chowdhury Sudhir R. , Pearson Carl M. , Gardner Gerald , Bratton Robert 
Published: December 2017

Twenty-eight healthy trained and untrained men and eleven untrained women were exercised at several grades on a treadmill or in various athletic events. The serum levels of five enzymes (two transaminases, aldolase, and two dehydrogenases) were compared prior to and at intervals after work. Generally there was a rise after exercise which reached its peak 5 min after completion of the work. The greatest increment of enzyme increase was observed in the untrained subjects and the least in the trained athletes. As the total amount of work output increased the mean serum enzyme levels were correspondingly raised. Aldolase and lactic dehydrogenase showed the least change, malic dehydrogenase increased moderately, while the two transaminases manifested very significant rises after all forms of exercise. Submitted on September 5, 1961
Heat exchanges of men during caloric restriction in the cold
Authors: Iampietro P. F. , Bass David E. 
Published: December 2017

The ability of men to maintain thermal balance during continuous cold exposure (14 days at 15.6 C, sedentary while nude) was assessed under four regimens of caloric intake: a) adequate, 2,800 kcal/day; b) moderate restriction, i.e., sufficient to maintain weight in a warm environment but without the added calories to support shivering, 2,600 kcal/day; c) marked restriction, 600 kcal/day; and d) complete starvation, 0 kcal/day. Respective weight losses for b, c, and d were 1.8, 8.2, and 12.2% body wt. With 600 and 0 kcal/day there was an impaired ability to maintain rectal temperature; under these conditions the men exhibited rectal temperatures 0.7 C lower than when they were on adequate or nearly adequate caloric intake. The men on complete starvation had the lowest heat production of all groups during later days in the cold; however, the data were too variable to demonstrate a close relationship between depressed core temperature and decreased heat production. It is concluded that marked restriction of calories is associated with depressed core temperatures during prolonged cold exposure, due in part to absence of specific dynamic action. Note: (With the Technical Assistance of Edward B. Green and John A. Vaughan) Submitted on April 30, 1962
Local adaptation to cold of Gaspé fishermen
Authors: LeBlanc Jacques 
Published: December 2017

This study indicates that Gaspé fishermen have a general peripheral adaptation to cold, since immersion of the hands and feet into ice water gave lower pressor responses than those observed in a control group. This local adaptation is maintained throughout the year. Immersion of the hands in hot water (47 C) reveals no significant differences between the fishermen and control subjects. The thermoreceptors, hypothalamus, cortex, and effector organs are suggested as sites of adaptation in this study. Submitted on May 3, 1962
Estimation of body fat in young women
Authors: Sloan A. W. , Burt J. J. , Blyth C. S. 
Published: December 2017

The body density of 50 healthy young women was determined by underwater weighing, and five skin-fold thicknesses and five girths were measured on each subject. The mean body density was 1.0467 g/ml (sd ± 0.0122), corresponding to 20.06 ± 4.63% by weight of fat in the body by the formula of Keys and Brozcaronek or 22.91 ± 5.58% by the formula of Siri. The mean specific gravity at water temperature 37.5 C was 1.0537 (sd ± 0.0122), corresponding to 22.13 ± 7.08% fat by the formula of Rathbun and Pace. The skin-fold measurement that showed the highest correlation with a composite criterion of skin folds was that over the iliac crest (r = +.92). The best prediction of body density was from skin-fold measurements over the iliac crest and back of arm, which gave a multiple correlation of –.74. Submitted on October 9, 1961
Bronchoconstriction in man following single deep inspirations
Authors: Lloyd Thomas C. 
Published: December 2017

Consistent small transient increases in airway resistance were observed to occur following maximal inspirations by a number of normal subjects. The same effect was also seen after merely attempting inspiration against a closed glottis, and both this and the response after deep inhalation were blocked by prior inhalation of a bronchodilator. An active bronchomotor mechanism is postulated for this response. Submitted on January 24, 1962
Computer analysis of curves from an infrared CO2 analyzer and screen-type airflow meter
Authors: Noe F. E. 
Published: December 2017

Curves from an infrared CO2 analyzer and a screen-type airflow meter were analyzed with a digital computer, and new curves were obtained. Practical applications are illustrated for the data and curves from the computer, and the significance of differences is discussed for the curves from normal, emphysematous, and obese subjects. Curves are shown for breaths with added dead space and for breaths after various periods of breath holding. Also included is a schematic diagram for an analogous analogue computer. Submitted on October 26, 1961
Stopped-flow measurements of CO and O2 uptake by hemoglobin in sheep erythrocytes
Authors: Sirs John A. , Roughton F. J. W. 
Published: December 2017

A stopped-flow method is described to measure spectrophotometrically the rates of uptake of CO and O2 by the hemoglobin of intact sheep erythrocytes. A comparison of the results obtained with the constant flow system has led to further refinement of the latter procedure. A linear relation is found between the rate of uptake and the concentration of the dissolved gas, and the initial percentage rate of saturation is independent of the concentration of the erythrocytes. Submitted on September 21, 1961
Water diuresis after hypnotic suggestion in hydropenic subjects
Authors: Hulet William H. , Shapiro Theodore , Schwarcz Benjamin E. , Smith Homer W. 
Published: December 2017

Four hydropenic female subjects who engaged in sham water drinking associated with suggested satiation of thirst during a short period of hypnosis responded by water diuresis of moderate magnitude after the termination of hypnosis. No evidence of water diuresis was observed under similar conditions in four male subjects, a circumstance possibly related to the effects of bladder catheterization. No significant increase in sodium excretion, sodium excretion fraction, or inulin clearance was observed in any instance. Submitted on April 9, 1962
Estimation of energy expenditure from expired air
Authors: Liddell F. D. K. 
Published: December 2017

Short cut methods of estimating energy expenditure from pulmonary ventilation are examined. Although for any one subject carrying out a particular task, the relationship between his energy expenditure and his ventilation is approximately linear, the equation of the regression line differs from task to task and, for any particular task, from subject to subject. Thus, the estimation of energy expenditure, for the generality of subjects and tasks, from pulmonary ventilation alone, by application of a single simple formula, is seen to be unacceptable as the estimates could be subject to serious error. Analysis of expired air cannot, therefore, be dispensed with but the calculations for estimating energy expenditure in terms of ventilation and the analysis of the expired air, already simplified by Weir, are shown to be even further reducible. A nomogram by which they can be carried out with negligible error is presented. Submitted on March 1, 1962
Vascular responses produced by histamine by ion transfer
Authors: Abramson David I. , Tuck Samuel , Zayas Agenor M. , Donatello Therese M. , Chu Luke S. W. , Mitchell Roscoe E. 
Published: December 2017

The vascular effects of histamine by ion transfer were studied in the hand and/or forearm of 25 normal subjects, using the venous occlusion plethysmographic method. Consistently a marked increase in blood flow was elicited in the hand and a lesser, but still considerable, augmentation occurred in the forearm. Histamine by ion transfer to the hand and foot produced significant vasodilatation in an opposite forearm, thus supporting the view that the drug is absorbed into the systemic circulation to affect distant vascular structures. Further evidence for such a belief was the flushing of the face and neck, associated with very little alteration in blood pressure and pulse rate. As a vasodilating agent, histamine by ion transfer was found to compare more than favorably with such agents as Mecholyl by ion transfer, ultrasound, short-wave diathermy, reflex vasodilatation, and wet heat. Submitted on September 10, 1962
Silver-silver chloride electrode as a nonpolarizable bioelectrode
Authors: Feder Walter 
Published: December 2017

A thermal-electrolytic method for the preparation of Ag AgCl electrodes suitable for measurement of bioelectrical changes in the microvolt range is given in detail. A potential of 0.5 mv or less between electrode pairs is easily attained; and such electrodes will accurately measure emf generated by both steady and fluctuating phenomena down to ±5 μv under routine laboratory conditions. Studies in the variations in potential for pairs of electrodes from the time they are introduced into the circuit until they reach a stable state, as well as long-term drift are presented. These data are analyzed in terms of activation, ohmic, and concentration polarization effects. Submitted on July 19, 1962
Effect of exercise on pulmonary diffusing capacity
Authors: Turino G. M. , Bergofsky E. H. , Goldring R. M. , Fishman A. P. 
Published: December 2017

The effect of graded exercise on the pulmonary diffusing capacity for both oxygen and carbon monoxide measured simultaneously was studied in healthy young adults by steady-state methods. Pulmonary diffusing capacity for oxygen increases progressively with increasing severity of exercise; it exceeds the DlCO at high levels of exercise by amounts greater than can be accounted for by the difference in diffusivity of the test gases. Diffusing capacity for carbon monoxide increases less than DlOO2 for comparable grades of exercise but no definite plateau value could be established. The supine or upright body position does not influence the values of either DlOO2 or DlCO during exercise. Diffusing capacity of the lung for oxygen does not limit the maximum levels of exercise which may be achieved by normal man. Submitted on August 6, 1962
Effect of a systemic A-V fistula and of pulmonary embolization on diffusing capacity
Authors: Williams M. Henry , Sobol Bruce J. 
Published: December 2017

Opening an aortic-caval fistula in anesthetized dogs was associated with slight but significant increase of the steady-state diffusing capacity of the lungs. Extensive pulmonary embolization with glass beads resulted in a slight and insignificant fall of the diffusing capacity. Increased pulmonary blood flow and obstruction to pulmonary arterioles do not appear to be associated with marked increase and decrease of the diffusing capacity. Submitted on October 5, 1962
Effect of hyperthermia on peripheral dark adaptation rates
Authors: Kissen Abbott T. 
Published: December 2017

Supersonic or hypersonic aircraft flight can produce hyperthermia in crew members. Dark adaptation is a physiologic response possibily influenced by such stress. Biochemical regeneration rate of rhodopsin might be altered if retinal blood or tissue temperatures are raised by this hyperthermia. Peripheral dark adaptation curves were obtained on five subjects at comfort (21.0 C) and 65.6 C temperatures alternately, using a modified Hecht-Schlaer adaptometer. In 24 heat experiments, subjects were exposed to 65.6 C ambient air temperature for 55 min after which the heat was shut off. Chamber temperature declined but the subjects remained in a relatively constant hyperthermic condition during the subsequent 35-min dark adaptation test. The criterion used here for hyperthermia is the elevation and maintenance of the rectal temperature at least 0.56 C above corresponding control temperature. Curves obtained under hyperthermic conditions (with the exception of the initial and terminal values) differ, with statistical significance, from controls, indicating a facilitation of dark adaptation under the imposed thermal stress conditions. Submitted on July 9, 1962
Contralateral effects of thermal stimuli on manual performance capability
Authors: Clark R. Ernest , Flaherty Charles F. 
Published: December 2017

The performance capability of one hand was studied as a function of its surface temperature and that of the contralateral hand. Three findings were determined to be statistically reliable for the subject sample tested: a) when the performing hand itself was cooled to a surface temperature of 40 F, performance decrements appeared which were independent of the temperature of the contralateral hand; b) when the performing hand was kept warm, cooling of the nonperforming hand resulted in an average reduction of 33% in the time typically needed for the completion of the manual task; and c) the surface temperature of a hand not exposed to the cold was found to fall an average of 2 F below its normal level when the contralateral hand was cooled to surface temperatures of 55 F or lower. Submitted on August 20, 1962
Body-temperature regulation in the normal and cold-acclimatized cat
Authors: Adams Thomas 
Published: December 2017

The role of the anterior hypothalamus as a temperature-sensible area serving a thermal regulatory input function for body-temperature control in cats living at 25 C (noncold acclimatized) or 5 C (cold acclimatized) was tested by selectively changing diencephalic temperatures in the unanesthetized animal resting at 23 C ambient temperature. Extremity and internal body-temperature and metabolic-rate responses were monitored during the induced thermal shifts. Both groups of animals showed greater peripheral vasomotor and internal body-temperature changes consequent to hypothalamic heating than cooling; no modification of these test patterns was noted as a function of whole-body cold acclimatization. The temperature-sensible anterior hypothalamic areas appear to be more influential in protecting against hyperthermia than hypothermia and their function in biothermal control does not appear to be altered by whole-body cold acclimatization. Submitted on November 1, 1962
Combined effect of cold and alcohol on heat balance in man
Authors: Andersen K. Lange , Hellstr⊘m B. , Lorentzen F. Vogt 
Published: December 2017

The combined effect of alcohol and cold on the heat balance of human subjects was studied by measuring heat production, deep body temperature, and skin surface temperature during an 8-hr night. Moderate doses of alcohol had no deteriorative effect on heat balance during prolonged mild cold exposure. The only noticeable effect of alcohol under these conditions is a hypnotic effect giving the subjects more comfort and sleep. If the cold stress becomes severe, some risk is involved by consuming alcohol, as an insufficient metabolic compensation was observed in one subject resulting in a greater drop of the rectal temperature than when the same subject rested nonintoxicated under the same environmental conditions. cold and alcohol Submitted on January 14, 1963
Cardiovascular responses to head-stand posture
Authors: Rao Shanker 
Published: December 2017

Reports of cardiovascular responses to head-stand posture are lacking in literature. The results of the various responses, respectively, to the supine, erect, and head-stand posture, are as follows: heart rate/min 67, 84, and 69; brachial arterial pressure mm Hg 92, 90, and 108; posterior tibial arterial pressure mm Hg 98, 196, and 10; finger blood flow ml/100 ml min 4.5, 4.4, and 5.2; toe blood flow ml/100 ml min 7.1, 8.1, and 3.4; forehead skin temperature C 34.4, 34.0 and 34.3; dorsum foot skin temperature C 28.6, 28.2, and 28.2. It is inferred that the high-pressure-capacity vessels between the heart level and posterior tibial artery have little nervous control. The high-pressure baroreceptors take active part in postural adjustments of circulation. The blood pressure equating mechanism is not as efficient when vital tissues are pooled with blood as when blood supply to them is reduced. man; heart rate; blood flow; skin temperature Submitted on January 3, 1963
Validity of heart rate as an indicator of cardiac strain
Authors: Maxfield Mary E. , Brouha Lucien 
Published: December 2017

Total cardiac cost is a measurement of the area under the curve obtained by plotting the heart rate for each minute during work and recovery. In a constant environment it varies with the work accomplished in a given time and, for a constant work performance, it varies with the severity of the conditions. The work accomplished per beat has a reciprocal relation to total cardiac cost when work and recovery times are constant. Recovery cost and the average of three early recovery heart rates, P1, P2, and P3, vary linearly with total cardiac cost when work or environmental stress increases. In these experiments P1, P2, and P3 are the heart rates per minute recorded during the last 30 sec of the 1st, 2nd, and 3rd min, respectively, of the recovery period. These recovery pulse rates provide a simple measurement of the degree of cardiac strain induced by work in any environment. cardiac cost; recovery pulse rates; work rate; warm environment; human male; human female Submitted on July 13, 1961