System monitors expired breath patterns simultaneously from four small animals after they have been injected with carbon-14 substrates. It has revealed significant quantitative differences in oxidation patterns of glucose following such mild treatments of rats as a change in diet or environment

Cole, A. O.

Feller, D. D.

Neville, E. D.

English

NASA Technical Reports Server

Dece'mber 1973
	
B73-10494 
NASA TECH BRIEF 
Ames Research Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Computer System for Monitoring Radiorespirometry Data 
A radiorespirometry—computer system has been 
developed which makes possible the monitoring of 
expired 14CO2 breath patterns simultaneously from 
four small animals after they have been injected with 
carbon-14 substrates. The system also can be used to 
monitor expired carbon dioxide patterns. It has re-
vealed significantly quantitative differences in oxida-
tion patterns of glucose following such mild treat-
ments of rats as a change in diet (20-hour fast) or as 
a change in environment (for example, increased 
is
 gravity by centrifugation). 
From an investigative as well as a diagnostic 
viewpoint, the technique of radiorespirometry offers 
many advantages, among which are: (1) Tests can be 
repeated on the same subject, and the subject can be 
his own control; as a result, data interpretation is less 
involved with pool size, compartmentalization, and 
recycling of the metabolic substrate. (2) The number 
of repetitive tests can be large since the substrate 
which is used is innocuous and easy to administer. 
Combination of the radiorespirometry technique 
with an on-line computer system offers important 
additional advantages: (1) Automatic corrections of 
equipment noise, delay times, and flow distortion; 
(2) Rapid calculation of normalized specific activity 
values; (3) Improved accuracy by large increase in 
number of calculation operations; (4) Real-time dis-
play of data, as well as rapid (10 to 20 minutes) print-
out of specific activity curves and calculated data 
tables. 
The radiorespirometry technique described briefly 
as follows is not significantly different from that in 
prevalent use. After injection with a 14C-labeled sub-
strate, such as 14C-bicarbonate or 14C-glucose, etc.,
animals are placed in small hemispherically-shaped 
metabolism cages. Respiratory gases from each of the 
four metabolism cages are transferred to a respir-
ometry system for analysis of total CO2 by infrared 
and analysis for '-CO2 by an ionization chamber—
electrometer. Analytical data from the respirometry 
systems are then processed by an on-line computer. 
Prior to each test, electronic noise and voltage dif-
ference in each respirometry system is subtracted by 
the following calibration procedure: The output of 
the respirometry system at zero setting is recorded 
for 5 minutes while a CO 2-free carrier gas purges the 
system; the output is averaged by the computer and 
set to zero. A constant flow of caIibratin, 1 gas (14CO2/ 
12 CO2) is introduced into the system and the output 
recorded for 5 minutes after peak output is reached; 
the output is averaged by the computer to build an 
internal calibration of mV-output vs concentration, 
which is used to calculate experimental outputs. 
The analog outputs of the respirometers may be 
sent simultaneously to an analog tape recorder for 
permanent storage and to a small computer (4K 
memory) where the data are processed to give digital 
printout of 14CO2, '2CO2, percent recovery, and cu-
mulative sum of CO2 at 1-minute intervals. However, 
only one respirometry system can be processed at a 
time because of the slow teletype printout and the 
limited computer memory. Optionally, an intertie 
can be made with a time-sharing terminal to a large 
computer (32K memory) equipped with high-speed 
printout, visual display, and X-Y plotter; thus, the 
rapid computation of various models, peak time, 
constants, and other ratios can be made for four res-
pirometry systems at one time. In this instance, the 
(continued overleaf) 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19730000494 2020-03-17T07:34:08+00:00Z
small computer becomes the data-acquisition console 
where data are sampled multiply and averaged at 1-
minute intervals; the condensed data are fed to the 
large computer by an interrupt mode when the small 
computer memory is full. The tape recorder becomes 
an auxiliary output file as a backup in case of com-
puter failure. 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: TSP 73-10494
Patent status: 
NASA has decided not to apply for a patent. 
Source: David D. Feller, Edwin D. Neville, 
and Arden 0. Cole 
Ames Research Center 
(ARC-10784)
. 
. 
B73-10494	 Category 05


Computer system for monitoring radiorepirometry data

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