bluuebunny/crossref_metadata_2025 huggingface dataset:
Duct flow and mitral regurgitation during changes of oxygenation in newborn swine
Authors: Rowe R. D. , Sinclair J. D. , Kerr A. R. , Gage P. W.
Published: December 2017

Mitral regurgitation and blood flow through the ductus arteriosus were quantitated during acute changes in oxygenation in 20 newborn swine studied under open-chest conditions during ventilation with 21, 100, or 10% oxygen. Mitral regurgitation and duct flow were estimated from the abnormally early deflections on dilution curves recorded from the left atrium, when compared with those from the aorta, following injection of indicator into the left ventricle. The induction of acute hypoxia resulted in highly significant increase of shunt through the patent ductus arteriosus (P @#X003d; 0.001). On reoxygenation this shunt diminished significantly (P @#X003d 0.01). These effects were present in animals up to 48 hr of age, although the younger animals sometimes had appreciable duct flow under normal conditions of oxygenation while older animals required longer periods of hypoxia to make duct flow evident. The findings support the evidence of previous studies that oxygenation has a marked effect on the patency of the ductus arteriosus. In the same conditions mitral regurgitation was always insignificant.

ductus arteriosus flow; hypoxia

Submitted on February 17, 1964
Measurement of left ventricular volume by thermodilution: an appraisal of technical errors
Authors: Rolett Ellis L. , Sherman Herbert , Gorlin Richard
Published: December 2017

An analysis of the technical errors inherent in the determination of left ventricular volume by indicator-dilution methods, particularly thermodilution, is presented. Inaccuracies in the measurement of the true rate of indicator washout from the ventricle are related to valvular regurgitation, heat transfer between ventricular wall and chamber, and a long sensor time constant; variations occur due to heterogeneous indicator mixing in the chamber and at the transducer. It is shown that, whatever the reason for error, it multiplies as the fraction of ventricular emptying becomes smaller. The error is reduced through the use of a sensor with an appropriately short time constant and through the acquisition of multiple dilution curves and stroke volume measurements. An estimate of the relative error in the computed left ventricular volume is possible and only under optimal circumstances is close to that found in the determination of cardiac output. The remaining variation in computed volume is primarily an indication of variable indicator mixing. The conditions required for reliability are extensive and place restrictions on the general usefulness of the method.

indicator-dilution technic; end-diastolic volume; residual volume; thermistor

Submitted on October 29, 1963
Cerebral metabolism of doubly labeled glucose in humans in vivo
Authors: Sacks William
Published: December 2017

With glucose-3-C14 as injected substrate, the production of C14O2 almost kept pace with the net uptake of C14 by brain. Brain C14O2 specific activities practically coincided with venous blood glucose specific activities. This rapid production of C14O2 with little or no dilution of C14 led to the derivation of theoretical curves for glucose-2-, glucose-1-, or glucose-6-C14 experiments. The dissimilarity between theoretical and experimental values suggested that there is a significant dilution of C14 in traversing the Krebs cycle. Equations derived from hypothetical metabolic pathways which included a pool of substrate, x, were employed to match theoretical with average experimental values. In experiments with doubly labeled glucose-C14-T, brain TOH (tritiated water) specific activities were used to derive brain C14O2 specific activity values which closely approximated actual results. A scheme for human cerebral metabolism of glucose in vivo, which includes a small, metabolically active pool of glutamate, ggr-aminobutyrate, and succinic semialdehyde, is proposed.

brain glucose oxidation; in vivo brain metabolism; isotopic glucose metabolism; glucose-C14-T cerebral metabolism

Submitted on February 3, 1964
Sweat suppression by forced breathing in man
Authors: Albert Roy E.
Published: December 2017

Thermal sweating from the forehead was suppressed by forced air breathing in two normal male subjects. The decreased sweat rate was associated with symptoms of respiratory alkalosis. This sweat suppression was blocked by the introduction of excess carbon dioxide into the respired gas.

sweating and hyperventilation; hyperventilation and sweating; respiratory alkalosis and sweating

Submitted on February 7, 1964
Variation of plasma ketones and free fatty acids during acute cold exposure in man
Authors: Hanson Peter G. , Johnson Robert E.
Published: December 2017

We have studied the magnitude of ketosis induced during acute cold exposure. Plasma and urinary ketone bodies and plasma free fatty acids (FFA) were followed in four healthy young men at rest during a 90-min period of seminude exposure to 0 C in still air. This period was followed by 4 hr of recovery at 25 C. Each subject served as his own control throughout an experimental sequence in which one cold-exposure and corresponding control period (25 C) were experienced each week for 3 successive weeks. The subjects were in a fasting state but with water ad libitum beginning 12 hr prior to the experiment. Light weight clothing was worn during recovery and control periods. The combined group data show a significant increase in plasma FFA during cold exposure as compared with similar control periods. Although true hyperketonemia or hyperketonuria did not develop, the levels of plasma ketones are elevated in the cold-exposure period of the first week. During the second and third week there is no difference between the cold and control plasma ketone concentration. The data suggest that FFA is mobilized as a metabolic substrate during cold exposure and that efficient peripheral utilization of the elevated plasma FFA concentration minimizes hyperketogenesis.

ketone bodies; metabolism; nonesterified fatty acids

Submitted on April 27, 1964
Agreement of cardiac outputs calculated from paired indicator-dilution curves
Authors: Opdyke David F.
Published: December 2017

Cardiac outputs calculated from paired dye-dilution curves obtained by sampling simultaneously from two sites in the pulmonary arteries were compared. Similar comparisons were made between paired cardiac outputs derived from pulmonary artery and left atrial dye-dilution curves, from pulmonary artery and descending aorta curves, and from two sites in the descending aorta. Paired cardiac outputs derived from two sampling sites in the pulmonary arteries agreed better than paired estimates derived from the pulmonary artery and either left atrium or descending aorta. Poorest agreement was found when paired outputs derived from the pulmonary artery and descending aorta were compared. Paired outputs from two sites in the descending aorta agreed somewhat better than comparable pairs from pulmonary artery and either left atrium or descending aorta.

Note:

(With the Technical Assistance of John McMorrow, Bruce Brundage, Albert Gosen, and Rose Apostolico)

agreement of paired cardiac outputs; cardiac output; output calculated from paired dye curves

Submitted on February 17, 1964
Effect of lipemia and heparin on arterial carbon dioxide tension
Authors: Barboriak Joseph J. , Kory Ross C. , Hamilton Lyle H. , Helman Sandy I.
Published: December 2017

Intravenous injection of heparin to lipemic subjects was followed by a rapid rise in arterial Pco2, amounting to 4.7 mm Hg 15 min after the injection; the alveolar Pco2 did not seem to be affected. In fasting subjects the postheparin rise in arterial Pco2 was less pronounced. Subsequent studies showed that the observed Pco2 rise occurred in vitro in the drawn blood and was due to an accumulation of unesterified fatty acids, liberated by the heparin-induced lipoprotein lipase.

respiratory gases; arterial blood gases; blood pH; a-A Pco2 gradient; lipoprotein lipase

Submitted on June 18, 1964
Safe exposure of men to severe heat
Authors: Bell C. R. , Hellon R. F. , Hiorns R. W. , Nicol P. B. , Provins K. A.
Published: December 2017

Eight men were exposed to hot environments which ranged from 37 C/30 C to 63 C/47 C dry- and wet-bulb temperatures. They remained in the heat until they showed signs of distress just before collapsing. The time taken to reach this state was found to be hyperbolically related to the severity of the environment when this was expressed as a weighted sum of wet- and dry-bulb temperatures. Separate hyperbolae were found for standing and working subjects. After the deduction of a suitable safety margin, the resulting curves and their equations make possible the prediction of safe exposure times for severe heat

heat stress; heat collapse; heat tolerance

Submitted on May 13, 1964
Isometric cross-transfer effects under conditions of central facilitation
Authors: Kroll Walter
Published: December 2017

Fifteen male subjects were given 16 trials of isometric flexion under two test conditions for each limb. Condition 1 consisted of odd-numbered trials being separate unilateral and even-numbered trials simultaneous bilateral contractions. In condition 2, the first 11 trials were separate unilateral and the last 5 trials were simultaneous bilateral. There was no evidence of central facilitation effects due to simultaneous bilateral versus separate unilateral wrist flexion during fatigued or nonfatigued states or upon dominant or nondominant limbs. Analysis of variance revealed only the linear trend component was significant in fatigue curves accounting for all but a small percentage of the observed variation in strength in the four experimental conditions.

cross education; proprioception

Submitted on June 11, 1964
Effects of cold exposure and exercise in a wet, cold antarctic climate
Authors: Budd G. M.
Published: December 2017

Six men were studied before and after 6 weeks of strenuous outdoor work and cold exposure—often in wet clothing—on Heard Island in the Antarctic. Physical fitness increased significantly, while subcutaneous fat and arterial blood pressure decreased significantly. The response of rectal temperature and shivering to a 2-hr period of whole-body cooling did not change significantly (although shivering tended to decrease), suggesting that the reduction in insulation caused by loss of fat was balanced by an increase in the insulation of other tissues. Finger temperature fell more rapidly, there was less cold vasodilatation, and the gradient of skin temperature between elbow and finger increased significantly, suggesting that heat was conserved by means of countercurrent heat exchanges and enhanced vasoconstriction. Discomfort from cold did not change. These results support those of a previous study at Mawson, Antarctica. Frostbite of one subject's hands, which grossly impaired touch sensation and caused marked intolerance to cold, produced no obvious changes in the response to cold of finger temperature.

vasomotor adaptation to cold; cold vasodilatation; tissue insulation; subcutaneous fat; shivering; subjective responses to cold; frostbite sequelae; finger temperature before and after cold injury; physical fitness; acclimatization to cold

Submitted on September 8, 1964
Aerobic work capacity in middle-aged Norwegian men
Authors: Andersen K. Lange , Hermansen Lars
Published: December 2017

Maximal oxygen uptake and related respiratory and circulatory functions were measured in sedentary and well-trained middle-aged men. Maximal oxygen uptakes averaged 2.63 liter/min in sedentary men and 3.36 liter/min in well-trained men, the latter value being essentially the same as found in young untrained students. The heart rate/ oxygen uptake relationship was found to be the same for sedentary-living men, regardless of age, but maximal heart rate was lower in older men. The maximal heart rate is probably the same in well-trained as in sedentary middle-aged men, this in contrast to what has been observed in younger age groups, where training reduces maximal heart rate. The exercise-induced hyperventilation takes place at an oxygen uptake corresponding to 70–80% of the capacity, this being the same in trained and untrained, and essentially the same as found in young adult subjects.

maximal O2 uptake

Submitted on March 23, 1964
Increase in breathing frequency following the reflex deep breath in anesthetized cats
Authors: Reynolds Leslie B. , Hilgeson Mata D.
Published: December 2017

In anesthetized cats, the inspiration-augmenting reflex, manifested as a spontaneous deep breath, was followed by a transient increase in breathing frequency in 66.5% of 382 cases observed. To determine whether this frequency increase was a property of altered mechanical properties of the lungs or was a property of the reflex itself, intact animals had their lungs inflated under conditions which would elicit the reflex as well as under conditions in which the reflex was absent. In all cases, dynamic lung compliance increased when the lungs were stretched. When the augmenting reflex was absent, breathing frequency decreased with increasing stretch. However, when the reflex occurred, breathing frequency increased to a maximum at a lung stretch of two and one-half times tidal volume. Frequency effects observed could be attributed to a combination of slowing by lung stretch and reflex speeding effects. The inspiration-augmenting reflex is proposed as a possible contributing mechanism to the tachypnea associated with lung conditions in which compliance is low.

lung compliance; inspiration-augmenting reflex; breathing frequency changes; pulmonary airflow resistance; control of respiration; reflex tachypnea

Submitted on May 18, 1964
Continuous recording of C14O2 excretion and O2 consumption by rats
Authors: Simpson-Morgan M. W.
Published: December 2017

An apparatus is described with which the O2 consumption and C14O2 excretion of small laboratory animals can be recorded and integrated continuously during the course of experiments with C14-labeled compounds. In addition, the total CO2 production throughout intervals can be determined and the respiratory quotient calculated. The oxygen consumption apparatus is simple, inexpensive, and sensitive, and can be used in any closed metabolism system.

apparatus; isotope; oxidative metabolism

Submitted on July 10, 1964
Intertissue diffusion effect for inert fat-soluble gases
Authors: Perl William , Rackow Herbert , Salanitre Ernest , Wolf Gerald L. , Epstein Robert M.
Published: December 2017

An approximately constant 5% difference in alveolar concentration of nitrous oxide and cyclopropane exists when these two gases are administered simultaneously to human subjects. This difference in uptake cannot be fully explained within the traditional framework of a perfusion-limited, multi-compartment model of inert gas exchange. It is proposed that this difference reflects direct diffusion from lean to neighboring adipose tissue through distances of the order of 1 mm. The diffusional rate of cyclopropane uptake into adipose tissue is initially large relative to perfusional uptake. The two rates eventually become and remain comparable as both decrease to zero. Implications of these results for deduction of blood flow to body adipose tissue by gas uptake measurement, and for utilization of capillary exchange surface by fat-soluble gases in adipose tissue are discussed.

compartment model generalization; gas uptake in body; inert, fat-soluble gas uptake; kinetics of gas exchange in body; body uptake of inert gases; fat-soluble gas uptake; distribution kinetics of gases in body

Submitted on February 3, 1964
Measurement of intrabronchial pressure in man
Authors: Macklem Peter T. , Wilson N. J.
Published: December 2017

By measuring total and lateral airway pressures in intact normal man, simultaneously with esophageal pressure, volume, and flow, it was possible to estimate the pressure difference across the wall of the airway, the pressure-flow curves of various segments of the airway, and the compliance of the airway. The results showed that: 1 Expiratory airway compression only occurs between the segmental bronchi and the glottis at volumes between 75 and 25% VC. 2) Expiratory flow is limited by compression of these airways. 3) The resistance of airways between segmental bronchi and trachea is variable, being markedly affected both by lung volume and pleural pressure. Tracheal resistance varies little with lung volume, but considerably with pleural pressure. The resistance of the airways between alveoli and segmental bronchi varies with lung volume but little with pleural pressure. These are probably the major resistance airways during quiet breathing. 4) Airway compliance is inversely related to lung volume. 5) The Bernouilli effect is large in large airways and helps to limit expiratory flow.

bronchial pressure; airway resistance; airway compliance; maximal expiratory flow; equal pressure point; lung mechanics; airway compression

Submitted on November 5, 1964
Cardiopulmonary effects of continuous pressure breathing in hypothermic dogs
Authors: Salzano J. , Hall F. G.
Published: December 2017

Continuous pressure breathing was studied in hypothermic anesthetized dogs. Alveolar ventilation decreased during continuous positive-pressure breathing and increased during continuous negative-pressure breathing. The changes in alveolar ventilation were due to changes in respiratory rate as well as in respiratory dead space. Cardiac output fell significantly during continuous positive-pressure breathing due to a reduction in heart rate and stroke volume. During continuous negative-pressure breathing cardiac output was only slightly greater than during control as a result of a fall in heart rate and an increase in stroke volume. Oxygen consumption was reduced to 60% of control during continuous positive-pressure breathing of 16 cm H2O but was 25% greater than control during continuous negative-pressure breathing. Qualitatively, CO2 production changed as did O2 consumption but was different quantitatively during continuous negative-pressure breathing indicating hyperventilation due to increased respiratory rate. Mean pulmonary artery pressures and pulmonary resistance varied directly with the applied intratracheal pressure. The results indicate that the hypothermic animal can tolerate an imposed stress such as continuous pressure breathing and can increase its oxygen consumption during continuous negative-pressure breathing as does the normothermic animal.

hypothermia; respiratory dead space; metabolic rate; cardiac output

Submitted on December 8, 1964
Effect of vertical vibration on respiratory airflow and transpulmonary pressure
Authors: Zechman Fred W. , Peck Davis , Luce Edward
Published: December 2017

The response of the human thoracoabdominal system to whole-body, vertical, sinusoidal vibration has been studied. Peak acceleration of the shake table was held constant (±0.5 G), and frequency varied between 2 and 10 cycles/sec. Subjects were seated with trunk axes parallel with the direction of acceleration. The amplitude of forced airflow oscillation increased with frequency to an average 1,368 cm3/sec at 6 cycles/sec and then decreased. The maximum average volume of air forced in or out of the lung with vibration was 46 cm3 at 5 cycles/sec. Transpulmonary pressure fluctuation exhibited a peak average amplitude of 5.44 cm H2O at 5 cycles/sec. The response to square-wave table motion was also investigated. The transient flow oscillation produced by the step function had an average frequency of 5.6 cycles/sec. Measurements of the logarithmic decrement of transient flow oscillation indicate the total thoracoabdominal system is underdamped (hV = 0.1–0.2). The calculated damping for the lung subsystem indicates very high damping (hL = 4.5). Measurements of abdominal deformation produced by the step function suggest the transient flow oscillations result from close coupling of the lung to other components of the thoracoabdominal system.

Note:

(With the Technical Assistance of Tom Sharp, Roger Shannon, and Judith White)

whole-body vibration; periodic vertical acceleration; vibration-induced changes in respiration; oscillation; mechanics of thoracoabdominal system

Submitted on February 14, 1964
Effect of temperature on deoxygenation rate of human red cells
Authors: Lawson W. H. , Holland R. A. B. , Forster R. E.
Published: December 2017

The rate of deoxygenation of oxygenated human red cell suspensions was measured in vitro as a function of temperature from 7 to 42 C at constant Pco2 in a stopped-flow rapid-reaction apparatus. There is a linear relationship between the deoxygenation rate constant, kc, and the reciprocal of the absolute temperature; the “activation energy” of 16,743 cal/mole agreed reasonably well with that predicted by theory, 14, 565. At 42 C deoxygenation was half complete in 0.04 sec while at 7 C the half-time was slowed to 0.8 sec. If the red cell transit time in tissues cooled to 7 C approximates the normally accepted value at 37 C of about 1 sec, the rate of red cell deoxygenation would be a limiting factor in the supply of oxygen to the peripheral tissues in the cold.

capillary diffusion; respiration; stopped-flow rapid-reaction apparatus

Submitted on May 14, 1964
Mixing of dye and blood in the canine aorta
Authors: Krovetz L. Jerome , Benson Robert W.
Published: December 2017

Paired simultaneous arterial sampling curves from both femoral or iliac arteries of 10 dogs were obtained following injections of indicator in the superior vena cava (SVC), right atrium (RA), left ventricle (LV), aortic root (AR), and descending thoracic aorta (DA). Calculated paired cardiac outputs following injection into the SVC or RA showed an average difference of 5.8% (se 0.97). Injections into the LV were not significantly different in this regard, having an average difference of 6.3% (P < 0.85). Injections into the AR and DA showed progressive increases in the differences of the paired curves, averaging 9.9% and 23.1%, respectively. The degree of aortic mixing of blood and dye appears to be related to the distance available for such mixing. While this cannot be interpreted as evidence for the existence of laminar flow in arteries, the degree of any existing turbulence is inadequate for complete mixing.

hemodynamics; turbulence; indicator-dilution theory; branching; arterial branches; cardiac outputs

Submitted on October 2, 1964
Changes in blood plasma during progressive dehydration
Authors: Senay Leo C. , Christensen Margaret L.
Published: December 2017

Progressive dehydration of resting male subjects was accomplished by exposure to 43.3 C dry bulb, 29 C wet bulb for 12 hr. For control experiments, evaporative weight loss was replaced with 0.1% saline. For dehydrating subjects, the following relationships with evaporative weight losses were obtained: %Delta osmotic pressure = 1.14 (% evap wt loss) — 0.43; %Delta [Na+] = 1.37 (% evap wt loss) — 0.45; %Delta [K+] — 2.19 (% evap wt loss) — 1.29; %Delta hematocrit = 1.4 (%Delta evap wt loss) — 2.65. Comparison of dehydration with rehydration results indicated augmentation of plasma volume with fluids containing high concentrations of potassium. An average decrease in plasma volume of 13.6% (T-1824) from 2.5 to 11 hr after initial heat exposure in dehydrating subjects was accompanied by a 15.7% increase in total protein. Albumin increased 11.6% while globulin increase averaged 22.5%. Plasma protein fractions are not static during dehydration, probably due to augmentation of each protein fraction, particularly globulin. Measurement of plasma volume by T-1824 more likely indicates changes in protein concentration rather than plasma volume changes. A relationship between hematocrit changes and plasma albumin concentrations is suggested.

plasma sodium; plasma potassium; plasma osmolarity; hematocrits; plasma albumin; plasma globulins

Submitted on February 23, 1965
Respiratory and articulatory factors in wind instrument performance
Authors: Berger Kenneth W.
Published: December 2017

The intraoral air pressure, rapidity of articulation, and quantity of air used in trumpet performance were measured in 10 subjects. Samples were taken at the two extreme loudness levels, very loud and very soft, and at four tonal frequencies. In addition, samples were made from one subject at two more extreme tonal frequencies. Loud tones were found to require greater intraoral air pressure than soft tones and, to a lesser degree, tones of high frequency required greater air pressure than tones of low frequency. Rate of articulation was found to be independent of intensity or frequency. Loud tones required a greater quantity of air than did soft tones and the quantity of air required for loud tones appeared to be independent of frequency. On the other hand, for soft tones the mid frequencies required less air than did the extreme frequencies. A few intraoral air samples from other wind instrumentalists were obtained and these samples indicated that the trumpet requires greater intraoral air pressures than other wind instruments.

articulation; intraoral air pressure; music; respiration; trumpet performance

Submitted on September 14, 1964
Reaction of the chick to one atmosphere of oxygen
Authors: Weiss Harold S. , Wright Ronald A. , Hiatt Edwin P.
Published: December 2017

The white Leghorn chick between the ages of 2 and 7 weeks is markedly resistant to the toxic effects of 1 atm O2. Continuous exposure for as long as 4 weeks caused neither deaths, obvious morbidity, or signs of pulmonary damage on gross autopsy. Nevertheless the hyperoxia had some adverse effects, primarily reducing the growth rate to 75–25% of normal, reducing feed intake per unit body weight to 75% of normal, slowing respiratory rate by 31%, decreasing erythrocytes, hemoglobin, and hematocrit by 9– 12%, and causing some reversible histological changes in the lungs. Arterial O2 tensions were elevated over 300 mm Hg, but arterial Pco2 and blood pH were unaffected. No residual effects were noted upon return to air breathing. The anatomical peculiarities of the avian lung may play some role in the chicks resistance to hyperoxia, but it is also possible that it is a function of age similar to the tolerance shown by the young rat but not the adult.

oxygen toxicity; chick respiratory system; artificial atmospheres; avian physiology; sealed systems

Submitted on February 8, 1965
Plasma catecholamines at high altitudes
Authors: Moncloa Federico , Gómez María , Hurtado Alberto
Published: December 2017

High altitude native residents and newcomers to a low ambient pressure (36 hr after arrival) have normal plasma levels of adrenaline and noradrenaline in the fasting condition. Thirty minutes after the intravenous injection of insulin the high-altitude residents show increase of epinephrine greater than in men living at sea level. These results are interpreted as a consequence of the lower glucose values observed at high altitudes.

high-altitude physiology; catecholamines and insulin; hypoglycemia in hypoxia

Submitted on February 12, 1965
Effects of altitude acclimatization on blood composition of women
Authors: Hannon John P. , Shields J. L. , Harris Charles W.
Published: December 2017

The effects of altitude acclimatization on blood composition were studied in eight University of Missouri (elev 700 ft) coeds who lived on the summit of Pikes Peak (elev 14,000 ft) for 10 weeks. During the period of altitude exposure the following changes were observed: a transient increase in heart rate, the maximum being reached on 1st day of exposure; an early rapid increase in hematocrit and hemoglobin which later became more gradual; an early and sustained reduction in plasma volume; a rapid initial increase and a more gradual later increase in plasma protein concentration which was attributable to elevations in both the albumin and the globulin fractions; a sustained decrease in the albumin-to-globulin ratio; a slight but sustained increase in serum oncotic pressure; a slight but sustained decrease in blood water content and serum osmolarity; and finally, an unaltered total leukocyte count, but a significant increase in lymphocytes and significant decrease in monocytes. It is concluded that the hematopoietic response to altitude is markedly less in women than that usually observed in men. In women at least, dietary iron supplementation enhances the rate of hematocrit increase at altitude. And finally, the loss of plasma volume is felt to be real and not due to simple dehydration.

high altitude; hypoxia; blood volume; blood hydration; plasma proteins; hematopoiesis; leukocytes; sex differences; iron supplement

Submitted on April 3, 1968
Effect of seasonal training on maximal cardiac output
Authors: Douglas F. G. V. , Becklake Margaret R.
Published: December 2017

(See PDF)

Page 602: footnote a to table 1 should read : aAge, 17 years; height, 170 cm; weight, 62 kg.
Prediction of body density from skin-fold and girth measurements of 17-year-old boys
Authors: Michael Ernest D. , Katch Frank I.
Published: December 2017

(See PDF)
Relationship of pulmonary artery pressure to exercise diffusing capacity (DLco)
Authors: Baker Duke H. , Daly Walter J.
Published: December 2017

We investigated the importance of pulmonary artery pressure (Ppa) and pulmonary blood flow PBF) in determining the increase in Dlcco observed during exercise. In 13 anesthetized dogs, an external right atrial reservoir was connected via a large-bore jugular vein catheter. Ppa, 10-sec-breath-holding Dlco, and PBF were measured during electrically induced exercise. Subsequent measurements were made during similar exercise while Ppa increases were prevented by varying the atrial reservoir level. In the control exercise situation, Dlco increased from 13.6 ± 6.4 at rest to 24.4 ± 9.2 ml/min x mm Hg; PBF from 3.68 ± 1.78 to 7.09 ± 2.82 liters/min; Ppa from 11 ± 4 to 23 ± 8 mm Hg; and O2 consumption from 131 ± 37 to 529 ± 249 ml/min. When Ppa was maintained at resting level during exercise sufficient to produce similar increases in O2 consumption, Dlco did not rise. This study shows: 1) exercise Dlco increases can be prevented if the Ppa increase is prevented; 2) an excellent statistical correlation between increased Dlco and increased Ppa during exercise but a similar correlation between increased PBF and increased Dlco was not established.

pulmonary diffusing capacity; Dl with exercise in dogs

Submitted on December 13, 1968
Lactate, ATP, and CP in working muscles during exhaustive exercise in man
Authors: Karlsson Jan , Saltin Bengt
Published: December 2017

The dynamics of lactate accumulation in working muscle was studied in three subjects performing maximal bicycle exercise of 2, 6, and 16 min duration. In separate experiments, the two longer maximal work periods were interrupted after 2 min and after 2 and 6 min, respectively. Biopsy specimens from the quadriceps femoris were obtained immediately after the work was terminated for determination of ATP, CP, glycogen, G-6-P and lactate. Blood lactate was also determined. The breakdown of the phosphagens (ATP and CP) was already maximal after 2 min of work in all experiments and averaged 2.7 and 3.6 mmole kg–1 wet muscle, respectively. The accumulation of lactate in the muscle and in the blood increased continuously until exhaustion and averaged in the muscle tissue both at the highest and medium loads 16.1 but was only 12.0 mmole kg–1 wet muscle at the lowest load. It is concluded that low ATP and CP stores in these experiments was not the reason for muscular fatigue. Further, if the muscle tissue lactate concentration was the reason for exhaustion on the two heaviest work loads another factor must be present to explain the exhaustion in the 16-min experiment.

exhaustion; muscle metabolites; muscle lactate; blood lactate; anaerobic metabolism; oxygen deficit
Effect of water immersion on renin-aldosterone and renal handling in normal man
Authors: Epstein M. , Saruta T.
Published: December 2017

Page 368: M. Epstein and T. Saruta. “Effect of water immersion on renin-aldosterone and renal handling in normal man.” Page 368: line 10, first paragraph of materials and methods, column 2, should begin: excretory rates....
Distribution of red and white blood cells in alveolar walls
Authors: Perlo S. , Jalowayski A. A. , Durand C. M. , West J. B.
Published: December 2017

Dog lungs were perfused with blood and rapidly frozen with liquid Freon gas at various pulmonary artery and venous pressures. The numbers of red and white blood cells per mm-2 of alveolar wall were counted in lung sections and, in addition, the proportion (by area) of the wall occupied by the cells was measured by point counting. The number and proportional area of the red blood cells rapidly increased as perfusing pressure was raised. These findings are consistent with earlier observations of capillary recruitment and distension. An unexpected observation was the large number of leukocytes in the capillaries especially at low perfusing pressures. For example when arterial exceeded alveolar pressure by 5 cmH2O (as occurs near the apex of the upright human lung), there were about 5,000 red cells and 4,000 white cells per mm-2 of alveolar wall. As perfusing pressure was increased, the number of leukocytes paradoxically decreased in zone 3 but remained constant in zone 2. Most of the white cells were mononuclear cells. These results suggest that the lung behaves as a mechanical sieve for large cells and that the number of trapped cells depends on the capillary pressure.
Effects of increased ambient pressure and nitrogen on man's monosynaptic reflexes
Authors: Bishop B. , Hoffman H. , Wallis I. , Shindell D.
Published: December 2017

Neurological signs during dives may result from altered excitability of central neurons. The present study assesses the effect of an increase in pressure from 1 to 3 ATA on the excitability of muscle spindles and alpha motoneurons by comparing the EMG amplitudes of the mechanically and electrically elicited monosynaptic reflexes of the gastrocnemius-soleus muscle in 10 normal adults breathing a normoxic oxygen-nitrogen gas mixture. At the surface the amplitude of the electrically elicited H response was matched to that of the mechanically elicited Achilles tendon reflex (ATR), but at depth these amplitudes became significantly different. In every subject the amplitude of the ATR, which depends upon the excitability of both muscle spindles and the alpha motoneurons, was reduced on an average of 38% (with a range of 12–75%). The H response bypasses the muscle spindles and hence, depends primarily upon alpha motoneuron excitability. Its amplitude was unaltered in four, reduced in three, and increased in three subjects. Since the ATR was always depressed despite the direction of change in the H response, we have concluded that an increase in ambient pressure (i.e., pressure per se, or nitrogen, or both) must have decreased the responsiveness of muscle spindles to the tendon tap via a reduction in fusimotor activity.
Correlation of acute with chronic hypoxic pulmonary hypertension in cattle
Authors: Will D. H. , Hicks J. L. , Card C. S. , Reeves J. T. , Alexander A. F.
Published: December 2017

We investigated acute and chronic hypoxic pulmonary pressor responses in two groups of calves, one bred to be susceptible, the other resistant to high-altitude pulmonary hypertension. Twelve 5-mo-old susceptible calves residing at 1,524 m increased their mean pulmonary arterial pressure from 26 +/- 2 (SE) to 55 +/- 4 mmHg during 2 h at a simulated altitude of 4,572 m. In 10 resistant calves pressure increased from 22 +/- 1 to 37 +/- 2 mmHg. Five calves were selected from each group for further study. When 9 mo old, the 5 susceptible calves again showed a greater pressor response to acute hypoxia (27 +/- 1 to 55 +/- 4 mmHg) than did 5 resistant calves (23 +/- 1 to 41 +/- 3 mmHg). When 12 mo old, the 5 susceptible calves also developed a greater increase in pulmonary arterial pressure (21 +/- 2 to 9 +/- 4 mmHg) during 18 days at 4,572 m than did the 5 resistant calves (21 +/- 1 to 64 +/- 4 mmHg). Acute and chronic hypoxic pulmonary pressor responses were highly correlated (r = 0.91; P less than 0.001) indicating that they were probably produced through a common mechanism.
Effect of chronic hypercapnia on body temperature regulation
Authors: Schaefer K. E. , Messier A. A. , Morgan C. , Baker G. T.
Published: December 2017

Guinea pigs and rats exposed to 15% CO2 for 7 days showed a parallel time course of changes in pH, body temperature (TB), and oxygen consumption (VO2). Between 1 and 6 h of exposure the maximal drop in actual pH occurred in guinea pigs simultaneously with the maximal fall in TB and VO2. During the subsequent period pH TB, VO2 rose again. Skin blood content (heat loss) also exhibited a biphasic pH-dependent time course. Animals showing no partial compensation of respiratory acidosis during 3 days exposure also failed in raising their TB back to normal in this time. The behavior of TB was found to be a good indicator of the acid-base status and adaptive potential of the animals to hypercapnia. Similar results were obtained in rats. Thermo-regulatory processes in the hypothalamus were affected during exposure to 15% CO2. Both guinea pigs and rats showed a decrease in norepinephrine content of the hypothalamus during the first part of exposure reaching a maximal fall at the end of 24 h. The serotonin content increased slightly during this period. During prolonged exposure to 3% CO2 for 7 days, TB showed a transient rise, and VO2 was slightly elevated.
Effect of heart rate on left atrial systolic shortening in the dog
Authors: Stone H. L.
Published: December 2017

The relationship between heart rate and left atrial end-diastolic diameter (LAEDD) and left atrial systolic shortening (LASS) was investigated in 12 conscious dogs. Atrial pacing, vagal blockade, isoproterenol, and beta-adrenergic blockade were used to change heart rate and the inotropic state of the atrium. LAEDD decreased linearly as heart rate increased. LAEDD averaged 33.0 mm (+/- 0.6 mm SEM) and decreased by 3.2 mm (+/- 0.4 mm SEM) with a change in heart rate of 50 beats/min. The ratio of LASS/LAEDD decreased as LAEDD decreased with increasing heart rate, but there was less of a reduction in the ratio at the extreme levels of LAEDD change with isoproterenol and vagal blockade. Propranolol reduced LASS at any LAEDD. At lower heart rates the reduction of LASS with pacing could be corrected by returning LAEDD to near control levels with a rapid infusion of fluid. It is concluded that LASS is primarily dependent on LAEDD and the inotropic state of the atrium. At higher heart rates, though, some effect of frequency can be observed. Isoproterenol and vagal blockade (increased contractile state) reduced the dependence of LASS on LAEDD.
Exercise responses following ozone exposure
Authors: Folinsbee L. J. , Silverman F. , Shephard R. J.
Published: December 2017

We have tested the response of 28 subjects to a three-stage ergometer test, with loads adjusted to 45, 60, and 75% of maximum aerobic power following ozone exposure. The subjects were exposed to one of 0.37, 0.50, or 0.75 ppm O3 for 2 h either at rest (R) or while exercising intermittently (IE) (15 min rest alternated with 15 min exercise at approximately 50 W. sufficient to increase VE by a factor of 2.5). Also, all subjects completed a mock exposure VE, respiratory frequency (fR), mixed expired PO2 and PCO2, and electrocardiogram were monitored continuously during the exercise test. Neither submaximal exercise oxygen consumption nor minute ventilation was significantly altered following any level of ozone exposure. The major response noted was an increase in respiratory frequency during exercise following ozone exposure. The increase in fR was closely correlated with the total dose of ozone (r = 0.98) and was accompanied by a decrease in tidal volume (r = 0.91) so that minute volume was unchanged. It is concluded that through its irritant properties, ozone modifies the normal ventilatory response to exercise, and that this effect is dose dependent.
Integration of chemoreceptor stimuli by rostral brainstem respiratory areas
Authors: Saint John W. M. , Bond G. C. , Pasley J. N.
Published: December 2017

Ventilatory regulation by brainstem sites rostral to the midpontile level was assessed in decerebrate cats by comparing the effects of punctate pneumotaxic center lesions with those of midpontile transection. After either procedure, PACO2 was significantly elevated. Moreover an equal suppression of hypercapnia-induced minute volumes and maintenance, at some PACO2 levels, of minute volume responses to hypoxia was observed. Tidal volume elevations accounted for the maintenance of hypoxia-induced minute volumes. Following pneumotaxic center lesions, hypercapnia-induced tidal volumes were higher than those exhibited subsequent to midpontile transection. After carotid sinus nerve section, PACO2 was elevated and hypoxia-induced alterations were abolished. Bilateral vagotomy resulted in apneusis. These data demonstrate that, in the brainstem area examined, only the pneumotaxic center influences the PACO2 level or set point for respiratory activity. A locus of tidal volume generation is ascribed to rostral brainstem sites outside this pneumotaxic center. Data obtained support the hypothesis of a differential brainstem integration of peripheral and central chemoreceptor afferent stimuli.
Diaphragmatic activity and lung liquid flow in the unanesthetized fetal sheep
Authors: Maloney J. E. , Adamson T. M. , Brodecky A. V. , Cranage S. , Lambert T. F. , Ritchie B. C.
Published: December 2017

For some time it has been suggested that breathing movements are made “in utero” and recently measurements of tracheal pressure and lung liquid flow in chronic fetal preparations have led to the hypothesis that rapid changes in these parameters are the result of respiratory muscle activity. To test this hypothesis diaphragmatic electrical activity was measured in seven chronic unanesthetized fetal sheep preparations and correlated with lung liquid flow and tracheal pressure. Diaphragmatic activity led to a fall of tracheal pressure and movement of a small volume of lung liquid into the lung. After the activity ceased, tracheal pressure returned to normal and flow diminished to zero or was directed out of the lung. The breathing pattern was unassociated with the net movement of lung liquid out of the lung. A histogram of the interval between breaths revealed a changing pattern of activity throughout gestation. The pattern was significantly altered after premature delivery of one animal with a respiratory problem. These observations provide evidence that respiratory muscles are active “in utero” and that the pattern of activity changes throughout gestation.
Evaluation of a reservoir in the main excretory duct of rat submaxillary gland
Authors: Schneyer L. H. , Flatland R. F.
Published: December 2017

Cannulation of salivary gland main excretory duct at its oral opening is routinely used for collecting fluid, in situ, from the luminally perfused duct, or saliva from the stimulated gland. For perfusion of the main excretory duct, in situ, or for saliva collection, rat submaxillary gland is often the organ of choice, since electrolyte transport occurs at high rates both in the whole gland and in the main excretory duct. Recently, it has been reported that there is a pouchlike dilatation of the main excretory duct at its oral end, and that this dilatation may serve as a fluid reservoir. Because of possible effects of such a reservoir on measurements of electrolyte transport by the whole gland or the main duct segment, the size and form of the reservoir have now been examined. For this, techniques of histology, radiography, and microcatherization were employed. It was found that, while the functional volume of the reservoir exceeds that of the main duct proper, the time needed for displacement of reservoir fluid by perfusate or saliva would probably be only on the order of 1–3 min at higher rates of saliva or perfusate flow. Therefore, if adequate allowance is made for equilibration time, collection of saliva or luminal perfusate by oral cannula seems justified.
Regional vascular influences on tail-cuff measurements of drug-induced changes in systolic pressure
Authors: Bunag R. D. , Mueting N. , Riley E.
Published: December 2017

When drug effects are quantified using the tail-cuff method, changes in systemic arterial pressure are extrapolated from those occurring in the caudal artery. The validity of this extrapolation was tested in anesthetized rats by recording drug-induced changes in phasic arterial pressure simultaneously from catheters inserted into the lower abdominal aorta, carotid, and caudal arteries. Pressor responses to norepinephrine or angiotensin were of equal magnitude at all three sites, but phentolamine reduced systolic pressure in the aorta or caudal artery more than that in the carotid artery. Unlike previous discrepancies between carotid and tail-cuff systolic pressures, aortic hypotension caused by injections of phentolamine or pentolinium in awake normotensive or spontaneously hypertensive rats was accurately predicted by the tail-cuff method. Because drug-induced changes in diastolic pressure always varied much less than those in systolic pressure, should indirect measurement of diastolic pressure become technically feasible, it might be preferable for assessing drug effects on blood pressure.
Simultaneous counting of 85Kr in lung and myocardium during measurement of coronary blood flow
Authors: Belloni F. L. , Mohrman D. E. , Sparks H. V.
Published: December 2017

Coronary blood flow rate (ml-min-1–100 g-1) was estimated by a) measuring pump flow into the cannulated circumflex branch of the left coronary artery and dividing by the weight of perfused myocardium and b) measuring the clearance of 85Kr following intra-arterial injection (detection with a 2-in. crystal with cylindrical collimation). Although the correlation between the two measurements was relatively high (r equals 0.90), the line best fitting the data was 85Kr flow equals 0.55 pump flow + 25.6. We tested the possibility that the discrepancy between the two methods was primarily due to the counting of 85Kr removed from myocardium and delivered to lung. Relative efficiency of lung counting versus myocardial counting was determined as well as clearance pattern of 85Kr from lung in each dog. A simple mathematical model which assumes no recirculation of 85Kr to heart allowed correction of coronary clearance curves using this information. When corrected 85Kr flow equals 1.00 pump flow + 4.1 (r equals 0.90). Thus, the major systematic cause for the discrepancy between the two measurements under the conditions of this experiment appears to be simultaneous counting of 85Kr in lung and in myocardium.
Dipping cone to correct optical distortions at liquid surfaces
Authors: Alexander J. T. , Nastuk W. L.
Published: December 2017

A dipping cone attachment for use with a long-working-distance objective is described. The device eliminates degradation of the microscope image which occurs when microelectrodes are applied to single muscle fibers in vitro.
Disruption of the sarcolemma of mammalian skeletal muscle fibers by homogenization
Authors: Kerrick W. G. , Krasner B.
Published: December 2017

A new method has been developed for mechanically disrupting the sarcolemma of mammalian sketletal muscle fibers (sarcolemma nonfunctional). Single fibers were produced from small pieces of the soleus muscle of the rabbit by gentle homogenization in a relaxing solution in a tissue homogenizer. These fibers were found to be longitudinally intact, with a sarcomere spacing of approximately 2.1 mum, permeable to large molecules of 10,000 MW, sensitive to the chemical stimuli that cause Ca2+ to be released from the sarcoplasmic reticulum, and responsive to Ca2+ in the same manner as frog fibers skinned in the traditional manner. The single fibers were mounted in a tension transducer and steady-state tensions were recorded in test solutions of different Ca2+ concentrations. The data did not differ statistically from data similarly obtained in identically prepared fibers that, in addition, we had longitudinally split in half to ensure disruption of the sarcolemmal barrier to the diffusion of ions.