A microrespirometer for simultaneous measurement of O2-consumption and CO2-production and its use in determining the respiratory quotient of tissue cultures

1954 ◽  
Vol 7 (2) ◽  
pp. 303-317 ◽  
Author(s):  
F.J.A. Prop
Keyword(s):  
Simultaneous Measurement ◽  
Respiratory Quotient ◽  
Co2 Production ◽  
O2 Consumption ◽  
Tissue Cultures

GASEOUS METABOLISM IN PREMATURE INFANTS AT 32-34°C AMBIENT TEMPERATURE

PEDIATRICS ◽  
1964 ◽  
Vol 33 (1) ◽  
pp. 75-82
Author(s):  
Forrest H. Adams ◽  
Tetsuro Fujiwara ◽  
Robert Spears ◽  
Joan Hodgman
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Premature Infants ◽  
Rectal Temperature ◽  
Respiratory Quotient ◽  
Carbon Dioxide Production ◽  
Open Circuit ◽  
Co2 Production ◽  
O2 Consumption ◽  
Rate Of Increase

Thirty-four measurements of oxygen consumption, carbon dioxide production, respiratory quotient, and rectal temperature were made on 22 premature infants with ages ranging from 2½ hours to 18 days. The studies were conducted at 32-34°C utilizing an open circuit apparatus and a specially designed climatized chamber. Oxygen consumption and carbon dioxide production were lowest in the first 12 hours and increased thereafter. The rate of increase in O2 consumption was greater than that of CO2 production, with a consequent fall in respiratory quotient during the first 76 hours of life. A reverse relation of O2 consumption and CO2 production was found following the 4th day of life with a consequent rise in respiratory quotient. There was a close correlation between O2 consumption and rectal temperature regardless of age. A respiratory quotient below the value of 0.707 for fat metabolism was observed in 7 premature infants with ages ranging from 24 to 76 hours.

Simultaneous measurement of metabolic heat rate, CO2 production, and O2 consumption by microcalorimetry

1991 ◽  
Vol 194 (2) ◽  
pp. 413-417 ◽  
Author(s):  
R.S. Criddle ◽  
A.J. Fontana ◽  
D.R. Rank ◽  
D. Paige ◽  
L.D. Hansen ◽  
...  
Keyword(s):  
Simultaneous Measurement ◽  
Heat Rate ◽  
Co2 Production ◽  
O2 Consumption ◽  
Metabolic Heat ◽  
Metabolic Heat Rate

Effect of ambient temperature on respiratory quotient of lean and obese Zucker rats

1989 ◽  
Vol 256 (1) ◽  
pp. R236-R239 ◽  
Author(s):  
R. Refinetti
Keyword(s):  
Ambient Temperature ◽  
Cold Acclimation ◽  
Respiratory Quotient ◽  
Substrate Utilization ◽  
Co2 Production ◽  
Zucker Rats ◽  
O2 Consumption ◽  
Gaseous Exchange ◽  
Obese Zucker Rats ◽  
Ad Libitum

O2 consumption and CO2 production were measured in lean and obese Zucker rats under these conditions: thermal neutrality (acclimation and test at 25 degrees C), acute cold (acclimation to 25 degrees C and test at 15 degrees C), and chronic cold (acclimation and test at 15 degrees C). The respiratory quotient (RQ) of ad libitum-fed animals was 0.92 at neutrality, 0.87 at acute cold, and 0.77 at chronic cold. Lean and obese animals had comparable RQs under the three conditions. These results confirm previous investigations on the effect of ambient temperature on gaseous exchange in rats but fail to demonstrate a difference in substrate utilization in the metabolism of lean and obese Zucker rats.

Chloral Hydrate and the Carbon Dioxide Chemoreceptor Response: A Study of Puppies and Infants

PEDIATRICS ◽  
1982 ◽  
Vol 70 (3) ◽  
pp. 447-450
Author(s):  
Martin H. Lees ◽  
George D. Olsen ◽  
Kip L. McGilliard ◽  
James D. Newcomb ◽  
Cecille O. Sunderland
Keyword(s):  
Carbon Dioxide ◽  
Tidal Volume ◽  
Eye Movement ◽  
Chloral Hydrate ◽  
Nrem Sleep ◽  
Co2 Production ◽  
O2 Consumption ◽  
Rapid Eye Movement ◽  
Natural Sleep ◽  
Co2 Elimination

CO2 chemoreceptor function was assessed during natural sleep and following the administration of 100 mg/kg of chloral hydrate to 26 puppies. With chloral hydrate-induced sleep, there were no significant changes in ventilation or in CO2 chemoreceptor response. The ventilation and CO2 chemoreceptor response of a group of infants in natural sleep were compared with those of a group receiving 50 mg/kg of chloral hydrate. Tidal volume, O2 consumption, and CO2 elimination were slightly higher in the group given chloral hydrate. There was no difference in the CO2 chemoreceptor response. The proportion of time spent in rapid eye movement (REM) and non-rapid eye movement (NREM) sleep in chloral hydrate-induced sleep was similar to that occurring in natural sleep. Use of chloral hydrate stabilizes O2 consumption and CO2 production, and it greatly facilitates the assessment of chemoreceptor function in infants. The CO2 chemoreceptor response appears not to be altered in puppies or infants.

Fast-response whole body indirect calorimeters for infants

1993 ◽  
Vol 74 (1) ◽  
pp. 476-484 ◽  
Author(s):  
J. K. Moon ◽  
C. L. Jensen ◽  
N. F. Butte
Keyword(s):  
Eye Movement ◽  
Fast Response ◽  
Full Term ◽  
Whole Body ◽  
Co2 Production ◽  
Sleep Stages ◽  
System Response ◽  
O2 Consumption ◽  
Rapid Eye Movement ◽  
Term Infants

Portable whole body indirect calorimeters were constructed for full-term (2.5- to 8-kg) and preterm (1- to 2.5-kg) infants. A new calibration system significantly increased the accuracy of flowmeters and gas analyzers. Performance tests with N2 and CO2 infusions and butane combustion demonstrated that the error of individual measurements of O2 consumption and CO2 production were within +/- 2%. The measured error was close to the theoretical uncertainty of approximately +/- 1% calculated from test results of the flowmeters and gas analyzers. System response to a step change in butane combustion rate exceeded 90% within 2 min. Error of +/- 2% and response of 2 min are likely to be the practical lower limits for whole body infant indirect calorimeters with current technology. The calorimeters demonstrated a rapid increase in O2 consumption after feeding (preterm infants) and in the transition from non-rapid-eye-movement to rapid-eye-movement sleep stages (full-term infants).

Effects of glycogen depletion and work load on postexercise O2 consumption and blood lactate

1979 ◽  
Vol 47 (3) ◽  
pp. 514-521 ◽  
Author(s):  
S. S. Segal ◽  
G. A. Brooks
Keyword(s):  
Blood Lactate ◽  
Slow Component ◽  
Minute Ventilation ◽  
Co2 Flux ◽  
Work Load ◽  
Bicycle Ergometer ◽  
Co2 Production ◽  
O2 Consumption ◽  
Glycogen Depletion ◽  
Heavy Exercise

To study a possible relationship between blood lactate and O2 consumption (VO2) after exercise, 11 male subjects exercised on a bicycle ergometer at moderate and heavy work loads in both normal glycogen and glycogen-depleted states. At rest, glycogen depletion resulted in significantly lowered blood glucose and lactate concentrations, CO2 production (VCO2), respiratory exchange ratio (R), and minute ventilation (VE). With the exception of glucose, these variables changed more in response to heavy exercise (HE: 2 min at a mean of 1,750 kg.m/min) than to moderate exercise (ME: 2 min at a mean of 1,000 kg.m/min). At either work load, VCO2, R, and lactate showed consistently greater responses in the normal glycogen state. The slope of the initial component of the postexercise VO2 curve was unaffected by either work load or lactate. Although the slope of the slow component of the postexercise VO2 curve became significantly more negative after HE, it was unaffected by the level of lactate. These results are inconsistent with the hypothesis of a “lactacid O2 debt.” Exercise intensity was the predominant factor influencing the magnitude and kinetics of postexercise VO2. Glycogen depletion resulted in lower VCO2, R, and blood lactate, but higher VE during heavy exercise. The results suggest that factors, in addition to CO2 flux to the lungs, influence VE during exercise.

Respiratory stimulation by female hormones in awake male rats

1991 ◽  
Vol 71 (1) ◽  
pp. 37-42 ◽  
Author(s):  
K. Tatsumi ◽  
M. Mikami ◽  
T. Kuriyama ◽  
Y. Fukuda
Keyword(s):  
Tidal Volume ◽  
Ventilatory Response ◽  
Blood Gases ◽  
Male Rats ◽  
Co2 Production ◽  
Male Rat ◽  
O2 Consumption ◽  
Estradiol Treatment ◽  
Respiratory Stimulation ◽  
Ventilatory Response To Co2

The respiratory effect of progestin differs among various animal species and humans. The rat does not hyperventilate in response to exogenous progestin. The present study was conducted to determine whether administration of combined progestin and estrogen prompts ventilatory stimulation in the male rat. Ventilation, blood gases, and metabolic rates (O2 consumption and CO2 production) were measured in the awake and unrestrained male Wistar rat. The combined administration of a synthetic potent progestin (TZP4238) and estradiol for 5 days significantly increased tidal volume and minute expiratory ventilation (VE), reduced arterial PCO2, and enhanced the ventilatory response to CO2 inhalation (delta VE/delta PCO2). On the other hand, respiratory frequency, O2 consumption, CO2 production, and body temperature were not affected. The arterial pH increased slightly, with a concomitant decrease in plasma [HCO3-]. Administration of either TZP4238 or estradiol alone or vehicle (Tween 80) had no effect on respiration, blood gases, and ventilatory response to CO2. The results indicated that respiratory stimulation following combined progestin plus estradiol treatment in the male rat involves activation of process(es) that regulate tidal volume and its augmentation during CO2 stimulus.

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