bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of negative-pressure breathing on lung mechanics and venous admixture
Authors: Velasquez Tulio , Farhi Leon E. 
Published: December 2017

Anesthetized dogs in the supine position show a spontaneous decrease in total respiratory compliance and an increase in venous admixture to the pulmonary circulation. Both these changes can be increased by negative-pressure breathing and reversed by positive-pressure breathing. If the changes in total respiratory compliance are due only to changes in lung compliance and these in turn result directly from the closure of alveoli, the relationship between compliance and inspiratory and expiratory pressure allows one to determine the scatter of opening and closing pressures in the alveoli. The venous admixture measures blood flow through collapsed alveoli, and its relationship to the negative pressure applied indicates the perfusion of the alveoli collapsing with each increment in negative pressure. By studying simultaneously changes in compliance and venous admixture, and using two basic assumptions, the dog's lungs can be described as a system composed of some elements receiving nearly 50% of the ventilation and 20% of the perfusion, relatively unstable mechanically, and having a very high Va/ Q ratio, while the remaining air spaces receive the same ventilation, but 80% of the perfusion. lung compliance; atelectasis; ventilation-perfusion ratio Submitted on October 28, 1963
Relative contributions of the rib cage and the diaphragm to ventilation in man
Authors: Bergofsky Edward H. 
Published: December 2017

A plethysmographic method was used to partition the tidal volume into two components: that due to rib-cage expansion and that due to diaphragmatic descent. In 15 normal subjects, one-third of the tidal volume was effected by diaphragmatic descent during various situations, i.e., at rest, voluntary respiratory maneuvers, and breathing special gas mixtures. This technic was combined with measurements of intra-abdominal pressure changes in order to measure the extrapulmonary work done by the diaphragm. For ordinary breathing, this work was found to equal the total extrapulmonary work of breathing (rib cage plus diaphragm) measured by passive ventilation in a body respirator, indicating that the rib cage requires no work to move itself until tidal volumes greater than 1 liter are reached. thorax; work of breathing Submitted on October 24, 1963
Integrated muscle chamber-transducer system
Authors: Katzung Bert 
Published: December 2017

The design and construction of a muscle chamber and isometric transducer system suitable for many types of in vitro studies of muscle is described. The unit can be constructed without special machine tools from easily available materials. It provides a high degree of versatility and is particularly suitable for simultaneous mechanical and electrical recording. isometric transducer system Submitted on December 2, 1963
A mechanism for positioning devices inside large blood vessels
Authors: Evert J. F. , Fingerson L. M. 
Published: December 2017

In order to facilitate the positioning of various velocity sensing devices in arteries, several types of probe configurations and external controllers were developed. The most successful of these is small enough to use in arteries of 3@#X2013;4 mm or larger. It utilizes three legs placed around the end of a catheter-like probe. At the end of this probe the velocity sensor is placed, generally a hot film anemometer in this study. By the manipulation of the external controller the legs, which are mechanically connected to the controller, may be moved relative to one another so that the probe end will visit any point over a given cross section of artery. The controller may be calibrated in order to determine any probe position to @#X00b1;10% and also to measure the vessel inner diameter at the point of investigation. Brief constructional details of both probe tip and controller are given. positioning, catheter in vivo; velocity sensor positioning, blood flow; cross section exploring of vessels; diameter measuring of vessels; vessel cross section positioning; catheter positioning in vivo Submitted on January 27, 1964
Validity of phonoarteriographic blood pressures during rest and exercise
Authors: Mastropaolo Joseph A. , Stamler Jeremiah , Berkson David M. , Wessel Hans U. , Jackson Walter E. 
Published: December 2017

A modification of the auscultatory blood pressure method, the phonoarteriogram, was developed. The innovated method essentially is a modified amplifying stethoscope. The pressure in the cuff is recorded from a pressure transducer, and the systolic and diastolic criteria are recorded from a microphone. The phonoarteriogram gives the advantages of a permanent record, includes pulse rate and pulse sound data, is not affected by hearing acuity, permits determinations often denied using auscultation in high ambient noise and exercise conditions, and eliminates observer bias. Three hundred and forty resting determinations and 218 exercise determinations on 60 subjects indicated good agreement between the phonoarteriogram and auscultation. In 50 systolic and diastolic intra-arterial determinations before compression of the cuff, during rest and exercise from one subject, the phonoarteriogram was as valid as auscultation. In 56 intra-arterial determinations during deflation of the cuff, i.e., simultaneous with the indirect measurements, during rest and exercise from a second subject, the phonoarteriogram was less fallible than auscultation, particularly during exercise. Phonoarteriograms are valid, reliable, and objective blood pressure record blood pressure determination; auscultatory blood pressure; intra-arterial blood pressure; physical fitness testing; ausculation; effort or physical effort; exercise; exertion; fatigue; methods, physiological; instrumentation; pulse; work Submitted on January 16, 1964
Modifications of neural output signals by muscles: a frequency response study
Authors: Partridge Lloyd D. 
Published: December 2017

Computer-generated stimulus patterns were used to study the response of cat skeletal muscle to nerve signals of changing impulse rates. Isometric tension responses were recorded. This method of testing demonstrated that muscle introduces alterations into dynamic nerve signals which are not obvious when tested with only a single pulse or even with uniform tetanic trains of stimuli. Within the range of physiological response characteristics, muscle introduces large lags in the response. The importance of such lags in the stretch reflex and other feedback systems is emphasized. Muscle also shows less isometric response amplitude for rapid cyclic inputs than for inputs of nerve impulses which change slowly in rate. Graphs are presented which illustrate the differences in amplitude and lag effects introduced by muscle when dealing with pulse rate signals varying at different cyclic frequencies. feedback analysis; pulse rate modulation; lag; reflex; isometric response; muscle dynamics; movement Submitted on January 9, 1964
Distribution of ventilation in normal subjects from 7 to 45 years of age
Authors: Orzalesi M. M. , Hart M. C. , Cook C. D. 
Published: December 2017

Distribution of ventilation was investigated in 57 normal subjects of both sexes ranging in age from 7 to 45 years using the nitrogen washout method. Normal values for nitrogen clearance delay and the lung clearance index are presented for children and adults. No significant sex- or age-dependent difference was found in either of these parameters. The present data are compared with those in the literature. nitrogen washout; respiration in children and adults; distribution of inspired gas in children and adults; gas distribution Submitted on April 13, 1964
Body oxygen consumption and pulmonary ventilation in obese subjects
Authors: White Robert I. , Alexander James K. 
Published: December 2017

Postabsorptive body oxygen consumption (Vo2) and pulmonary minute ventilation (Ve) were measured 164 times in 109 very obese subjects at rest. A statistically significant relationship was found between Vo2 and total body weight. The correlation coefficients for the relationships between Ve and total body weight and Ve and body surface area were less significant. The mean calculated basal metabolic rate was within normal limits. The mean values for Vo2 in the obese subjects were considerably higher than those predicted at ideal weight, while the mean values for oxygen consumption per kilogram body weight were lower than those reported in normal subjects. The mean percentage increase in oxygen consumption per kilogram excess weight (ΔVo2/Δ kg) approached the value for percentage of cell mass in excess weight, suggesting that ΔVo2/Δ kg may be a function of the increment in cell mass with obesity. Similarly, since basal metabolic rate remained unchanged, proportionate increments in body surface area and cell mass appeared to occur with the development of obesity. obesity tissue, oxygen consumption Submitted on April 3, 1964
Hemodynamic responses to controlled 100% oxygen breathing in emphysema
Authors: Holt John H. , Branscomb Ben V. 
Published: December 2017

Cardiopulmonary hemodynamic responses to breathing 100% oxygen for 20 min were studied in 13 patients with moderate to severe chronic obstructive emphysema under conditions of controlled ventilation. A technique for regulating the level of ventilation in the unanesthetized subject is described. Cardiac output was measured by the indicator-dilution method. Arterial blood gas analysis and pH were performed in each phase of the study. A slight but statistically significant decrease in cardiac index occurred. There was a highly significant reduction in pulmonary arterial pressure and pulmonary vascular resistance. No change in heart rate, pulmonary wedge pressure, or aortic pressure occurred. It is concluded that oxygen breathing caused a release, in part at least, of a pulmonary vasoconstrictive element in these patients. pulmonary circulation; oxygen in pulmonary hypertension; hypoxia and pulmonary vasoconstriction; controlled ventilation during oxygen inhalation Submitted on May 27, 1964
Intra-arterial blood pressure during exercise with different muscle groups
Authors: A°strand Per-olof , Ekblom Björn , Messin Roger , Saltin Bengt , Stenberg Jesper 
Published: December 2017

In 13 subjects intra-arterial blood pressure, heart rate, blood lactate, oxygen consumption, and pulmonary ventilation were respectively measured during submaximal and maximal arm and leg exercise. Blood pressure usually increased linearly with the oxygen uptake, this increase being significantly more pronounced for arm than leg work. The site of the catheter, mostly the femoral artery, can partly account for the difference, recorded blood pressure being constantly higher in the resting limb. Nevertheless, simultaneously recorded pressures in arm and leg give significantly higher values during cranking. Larger increases in peripheral vascular resistance in the resting extremities during arm work as well as the important static work produced by cranking are possible explanations for this difference. This fact might have clinical interest. differences between arm and leg work; catheter position when measuring blood pressures; lactate production in small and large muscle groups Submitted on June 15, 1964
Energy metabolism in hypnotic trance and sleep
Authors: Jana Hrishikesh 
Published: December 2017

The energy metabolism of 14 healthy males was studied before and during a hypnotic trance in the basal state. Metabolic rates during the basal waking, the basal hypnotic trance and the basal sleep were also determined in three subjects for 3 consecutive days, respectively. It was observed that a hypnotic trance does not significantly influence the metabolic rates in a basal condition while natural sleep lowers the basal metabolic rates by 8.73%. hypnosis; oxygen consumption; carbon dioxide; elimination; respiratory quotient Submitted on April 7, 1964
Demonstration of bile stasis in the mouse by a direct and an indirect method
Authors: Plaa Gabriel L. , Becker Bernard A. 
Published: December 2017

Cannulation of the common bile duct of the mouse has been effected. Bile flow rates and bile pigment concentrations have been determined in these preparations. These values are lower than comparable values in bile duct-cannulated rats. An indirect test for detection of bile flow in the mouse, using injected fluorescein as an indicator, has been devised. Using all-or-none criteria, results obtained using the indirect technique correlate well with those obtained by the direct (cannulation) method. The use of the indirect test in conjunction with liver function tests, e.g., Bromsulphalein (BSP) retention, is recommended as a means of elucidating causes of liver dysfunction. By this means, a difference has been demonstrated between two hepatotoxic agents which effect BSP retention in the mouse: carbon tetrachloride and alpha-naphthylisothiocyanate (ANIT). The latter agent interferes with BSP excretion as shown by the indirect bile flow test; carbon tetrachloride does not cause blockage of bile flow. bile flow; alpha-naphthylisothiocyanate; CCl4; cannulation of bile duct in mice; fluorescein; measure of bile flow in mice; sulfobromophthalein; bile pigment concentration in mice Submitted on September 10, 1964
Thermal dilution: instrumentation with thermistors
Authors: James Gordon W. , Paul Milton H. , Wessel Hans U. 
Published: December 2017

Based on the steady-state small-signal equivalent circuit parameters for a self-heated thermistor, the relationship of flow versus temperature sensitivity is found to be linear with the power dissipated in the thermistor. For the thermistors considered (YSI 520 and 512 series) flow sensitivity is negligible at power inputs below .01 mw. This power applied to a thermistor incorporated into a balanced Wheatstone bridge provides an output signal of approximately 150 μv for a .1 C temperature change. Amplifier requirements for thermal dilution are: gain of 104, a frequency response of 25 cycle/sec or greater, and a peak noise referred to input of less than 2 μv. A calibration procedure using a fixed resistance bridge unbalance and calculations from measured thermistor parameters is discussed. The procedure is independent of changes in amplifier and recorder gain, or changes in bridge voltage and ambient temperature. The effect of thermistor aging on the procedure is considered and found to be quite small. A bridge circuit incorporating variable bridge voltage is described and the application of the variable bridge voltage to the in vivo estimation of the thermistor dissipation constant and flow effects are discussed. Intravascular temperature measurements in man and in the anesthetized dog indicate that changes in thermistor resistance periodic with pulse are primarily the result of intermittent contact of the thermistor with the vessel wall, and due to changes in both temperature and dissipation constant. temperature measurement; cardiac output Submitted on June 12, 1964
Design and performance characteristics of a respiratory valve for the dog
Authors: Zechman Fred W. , Orr Thomas B. , Brooks John 
Published: December 2017

Working drawings and performance characteristics are presented for a small respiratory valve. The valve has the following advantages: light weight (17 g), low flow resistance (0.6 cm H2O at 0.5 liter/sec), and a small dead space volume (8.5 ml). respiratory valve design; small animal respiratory valve Submitted on July 20, 1964
An electro-optical meniscus-sensing system for a pressurized flush bottle
Authors: Benson Robert W. , Schiebler Gerold L. , Krovetz L. Jerome , Sutterer William F. 
Published: December 2017

A pressurized flush bottle system is used in some laboratories to ensure patency of indwelling catheters and needles. Some method must be utilized to monitor the fluid level in the bottle since complete emptying of the fluid would allow air under pressure to pass into the circulatory system. An electro-optical device is described which will sense a predetermined level of saline. A light source is mounted in a bottle holder assembly almost opposite and slightly below a photoresistor. At any level of fluid, some light from the exciting lamp is reflected from the meniscus causing a shadow immediately above the fluid level. When the meniscus falls below the photocell level, the decrease in light intensity increases photocell resistance which causes the transistorized circuit to activate audio and visual warning devices. electro-optical warning device; exciting lamp; fluid transistorized circuit Submitted on October 26, 1964
Interrelation between lung volume, arterial CO2 tension, and respiratory activity
Authors: Woldring Sabbo 
Published: December 2017

In anesthetized cats with open thorax the activity of the respiratory muscles (diaphragm and abdominal muscles) is studied as a function of lung volume and arterial CO2 tension. It is shown that the sensitivity of the inspiratory muscles to a given change in lung volume (V) (Hering-Breuer reflex) varies with the arterial pCO2 level, and conversely, that the CO2 sensitivity of the inspiratory motor system is dependent upon the volume of the lungs. The relations are fairly linear and can be expressed by the equation: M — M0 = K (pa CO2 — p0) (V0 — V), in which M represents inspiratory motor activity and M0, p0, and V0 and K are constants. The activity of the expiratory muscles is not dependent on CO2. regulation of respiration; Hering-Breuer reflex; electromyography of respiratory muscles Submitted on September 24, 1964
A method for measuring deviations from equilibrium of the glucose anomers in blood
Authors: Hill John B. 
Published: December 2017

A method for detecting deviations from equilibrium values of β-d-glucose has been developed. This method is dependent upon the specificity of glucose-oxidase for β-d-glucose and the catalytic effect of hydroxyl ions on mutarotation. The method has been used to monitor the blood stream of anesthetized normal dogs and dogs given epinephrine, glucagon, or insulin. It has also been used with alloxan-diabetic dogs. Since the method will detect deviations from equilibrium when agr- or β-d-glucose infusions are given and since in the above situations no impressive deviations were seen, it has been concluded that in the anesthetized dog the glucose is at or very near equilibrium and that glucagon and epinephrine do not alter the equilibrium. monitoring blood glucose; epinephrine on glucose anomers; glucagon on glucose anomers; insulin on glucose anomers Submitted on August 24, 1964
Convenient apparatus for recording contractions of isolated heart muscle
Authors: Blinks John R. 
Published: December 2017

A simple and convenient apparatus for physiological or pharmacological experiments on preparations of isolated heart muscle is described. Provision is made for recording independently from two preparations mounted in the same bath. Electrodes for stimulation or recording are incorporated in the clamps that hold the tissue. The construction ensures the maintenance of a high oxygen tension at the surface of the tissue without the mechanical artifacts that result from bubbling oxygen directly past it. papillary muscle; isolated organ bath; isolated atria; double muscle preparation; circulating salt solution; stimulating electrodes; concentration-effect curves; inotropic and chronotropic effects; oxygenation Submitted on November 5, 1964
Polarographic determination of oxygen content and capacity in a single blood sample
Authors: Maio Domenic A. , Neville James R. 
Published: December 2017

A polarographic method was described in an earlier report which permits the accurate, rapid determination of oxygen content in small samples of blood. As with the Van Slyke technic, total oxygen capacity was formerly estimated by a separate determination of the oxygen content after complete saturation with oxygen of another portion of the blood sample. Further experience with the polarographic method has revealed the feasibility of estimating both content and capacity in a single blood sample. The capacity estimate is made possible by the polarographic observation of the quantity of potassium ferricyanide required to convert ferrohemoglobin to ferrihemoglobin. The measurement of oxygen content is performed, as previously described, by the polarographically determined increase in physically dissolved oxygen caused by the release of bound oxygen. By this means, one avoids sampling and random errors inherent in the use of two separate determinations. The method requires only a brief time for performance and ordinary technical proficiency. It is also simple in application. polarographic dropping mercury electrode; oxygen tension; digitonin; potassium ferricyanide; ferrohemoglobin; ferrihemoglobin Submitted on June 24, 1964
Renal function in high-altitude natives and in natives with chronic mountain sickness
Authors: Lozano Rodolfo , C. Carlos Monge 
Published: December 2017

When compared with sea-level residents, the healthy natives living at an altitude of 4,540 m show a 12% reduction in the glomerular filtration rate, a 37% reduction in effective renal plasma flow, a 12% reduction in effective renal blood flow, and an increase of 39% in the filtration fraction. The corresponding values in patients with chronic mountain sickness living at 4,300 m above sea level are: glomerular filtration rate, 32% reduction; effective renal plasma flow, 57% reduction; effective renal blood flow, 9% increase; and filtration fraction, 56% increase. The mean hematocrit values of the healthy and sick natives investigated were 59 and 79%, respectively. The possible relationships between cardiac output, hematocrit values, and renal hemodynamics are discussed. altitude stress; blood flow, kidney; glomerular filtration Submitted on October 5, 1964
Microphotoelectric plethysmography using a rabbit ear chamber
Authors: Asano Makishige , Yoshida Keiichi , Tatai Kichinosuke 
Published: December 2017

The total and segmental microphotoelectric plethysmographs (—m; MPPG) were developed by using CdS photoconductive cells and rabbit ear chambers. The former were obtained from a whole micro-circulatory unit and the latter from segmental vessels in the microcirculation of which images were projected on a focusing glass. Both record the dynamic behaviors of the microcirculation continuously and quantitatively, and permit microscopic observations. The total and segmental MPPGs reflect various fluctuations of vasomotion and of blood flow in the microcirculation. In the microcirculatory blood flow, rhythmic fluctuations of 4–8, 8–12, and 0.5 or fewer counts/min were distinctly noticed in addition to the basic rhythm of 1–3 counts/min. agrR wave; &szligbeta;R wave; ggrR wave; omegaR wave; rhythmic fluctuation in the microcirculation Submitted on April 29, 1964
Phase-sensitive detector-type electromagnetic flowmeter
Authors: Guha Sujoy K. , Richardson Alfred W. 
Published: December 2017

An improved 60 cycles/sec sine wave electromagnetic flowmeter has been developed. By special construction of the pickup cannula and phase-sensitive demodulation, the conventional “balancing” procedure has been eliminated. Thus the operational technique is simple, and the flowmeter does not need readjustment between use. Both forward and backward flows can be measured with less than 3% error. The frequency response as determined by the use of a suppressed carrier modulated signal was 0–30 cycles/ sec without loss. blood flow; 60 cycles/sec sine wave; suppressed carrier test Submitted on October 26, 1964