scholarly journals MEASUREMENT OF OXYGEN UPTAKE UNDER CONTROLLED PRESSURES OF CARBON DIOXIDE

1949 ◽  
Vol 179 (3) ◽  
pp. 1085-1091
Author(s):  
Arthur B. Pardee
Keyword(s):  
1960 ◽  
Vol 15 (4) ◽  
pp. 583-588 ◽  
Author(s):  
F. N. Craig ◽  
E. G. Cummings

Two men ran for 20 or 60 seconds while inhaling air, oxygen or 4% carbon dioxide. Inspired respiratory minute volume was determined for each breath. Ventilation increased suddenly in the first breath with minimal changes in end-expiratory carbon dioxide tension and respiratory exchange ratio to a rate that remained constant for 20 seconds before increasing further. The rate of carbon dioxide output was uniform during the first 20 seconds. A 12% grade did not increase ventilation or oxygen uptake during runs of 20 seconds, but in the first minute of recovery, ventilation was 64% greater than after level runs. Inhalation of oxygen inhibited ventilation by 24% in the 20-second periods before and after the end of a 60-second run. Inhalation of carbon dioxide begun at rest produced increments in ventilation and end-expiratory carbon dioxide tension that varied little during running and recovery. In the 20-second runs ventilation varied with speed but appeared independent of ultimate metabolic cost. Submitted on January 21, 1960


1966 ◽  
Vol 19 (5) ◽  
pp. 871 ◽  
Author(s):  
T O'shea ◽  
RG Wales

The addition of casein and lecithin to a phosphate-saline diluent in which ram and bull spermatozoa were cooled to 5�C increased their subsequent viability at 37�C and the effects were additive. Casein and lecithin also increased the metabolism of fresh ram semen. After storage at 5�C, oxygen uptake and oxidation of lactate by ram and bull spermatozoa were lower than before storage. The decrease in the amount of fructose oxidized to carbon dioxide was greater.


1980 ◽  
Vol 49 (5) ◽  
pp. 863-868 ◽  
Author(s):  
R. P. Adams ◽  
H. G. Welch

Six subjects rode a bicycle ergometer on three occasions breathing 17, 21, or 60% oxygen. In addition to rest and recovery periods, each subject worked for 10 min at 55% of maximal oxygen uptake (VO2 max) and then to exhaustion at approximately 90% VO2 max. Performance time, inspired and expired gas fractions, ventilation, and arterialized venous oxygen tension (PO2), carbon dioxide tension (PCO2), lactate, and pH were measured. VO2, carbon dioxide output, [H+]a, and [HCO3-]a were calculated. Performance times were longer in hyperoxia than in normoxia or hypoxia. However, VO2 was not different at exhaustion in normoxia compared with hypoxia or hyperoxia. During exercise, hypoxia was associated with increased lactate levels and decreased [H+]a, PCO2, and [HCO3-]a. The opposite trends were generally associated with hyperoxia. At exhaustion, [H+]a was not different under any inspired oxygen fraction. These results support the contention that oxygen is not limiting for exercise of this intensity and duration. The results also suggest that [H+] is a possible limiting factor and that the effect of oxygen on performance is perhaps related to control of [H+].


1962 ◽  
Vol 17 (1) ◽  
pp. 47-50 ◽  
Author(s):  
B. Issekutz ◽  
N. C. Birkhead ◽  
K. Rodahl

Oxygen uptake and carbon dioxide output were measured in 32 untrained subjects during exercise on the bicycle ergometer. It was shown that the work respiratory quotient (RQ) under standardized conditions can be used as a measure of physical fitness. ΔRQ (work RQ minus 0.75) increases logarithmically with the work load and maximal O2 uptake is reached at a ΔRQ value of 0.40. This observation offered the possibility of predicting the maximal O2 uptake of a person, based on the measurement of RQ during a single bicycle ergometer test at a submaximal load. For each work RQ between 0.95 and 1.15 a factor was presented, together with the aid of a simple equation, which gave a good approximation (generally better than ±10%) of the maximal O2 uptake.


1972 ◽  
Vol 52 (1) ◽  
pp. 57-63
Author(s):  
L. M. SANFORD ◽  
G. J. KING

Boar spermatozoa were diluted in Ringer’s fructose or sulfate buffer and incubated aerobically for 4 hr at 37 C (a) in the presence of potassium hydroxide (KOH), hyamine hydroxide, or diethanolamine (DEA) absorbents, and (b) in 1, 2, or 3% atmospheric levels of carbon dioxide. Oxygen uptake by boar spermatozoa was enhanced by the presence of DEA compared with KOH and hyamine hydroxide. Incubation with DEA resulted in increased spermatozoan livability, more desirable cell motion, and smaller increases in buffer pH. Oxygen uptake by boar spermatozoa was optimum with 1 or 2% carbon dioxide, depending upon which buffer cells were diluted in. Levels of 2 and 3% carbon dioxide maintained oxygen uptake and livability of boar spermatozoa during later stages of the incubation period equally as well as 1% carbon dioxide. As the level of atmospheric carbon dioxide increased, buffer pH remained closer to the initial value.


1983 ◽  
Vol 55 (8) ◽  
pp. 791-800 ◽  
Author(s):  
A.M. HENDERSON ◽  
P.C. FORRESTER ◽  
R.F. ARMSTRONG ◽  
C.A. MOSSE ◽  
D. HALSALL

1965 ◽  
Vol 25 (2) ◽  
pp. 123-128 ◽  
Author(s):  
Nirmal Chakravarty

Glycolytic activity of rat peritoneal mast cells has been measured by the Cartesian ampulla diver technique. The rates of anaerobic glycolysis, expressed as CO2 expelled from a bicarbonate medium, are 1.70 x 10-6 µl and 1.43 x 10-6 µl per cell per hour with and without glucose, respectively. The aerobic glycolysis rate in the presence of glucose, assuming the respiratory quotient to be 1, is 0.93 x 10-6 µl CO2 per cell per hour. It is pointed out that the anaerobic and non-respiratory aerobic carbon dioxide production by mast cells is much higher than the respiratory oxygen uptake reported previously. These values have been interpreted in terms of glucose utilization.


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