FREE ELECTRONIC LIBRARY - Dissertations, online materials

Pages:     | 1 ||


-- [ Page 2 ] --

Further support for APA, co./Ate as a factor in the control of ventilation at the onset of exercise is its close relationship to mean inspiratory flow rate (VT/TI). As an index of inspiratory drive (Milic-Emili, 1982), VT/TI correlates with both mouth occlusion pressure and ventilation during exercise (Siafakas, Morris & Prime, 1979). During the breath following an increase in exercise load, VT/TI increased in parallel with the increase in APA, Co2/Ate, but there was no change in VT' PA C02 or Rc02 Nor was the increase in APA, co,/Ate itself due to an increase in flow rate or to a change in the pattern of breathing. Systematic studies of these variables (Allen et al. 1984) have shown that the relationship between APA, C02/Ate and TC02o VT, and frequency of breathing (r.r.) during exercise can be described by a single multiple linear regression equation: APA, C02/Ate = 3-52 + 5-23 VCO2 - 2-23 VT-0-05 r.r. This relationship demonstrates that increases in VT or r.r. will decrease rather than increase APA, Co2/Ate during exercise, an effect predicted in a theoretical model by DuBois, Fowler, Soffer & Fenn (1952).

The mechanism by which APA co./Ate is linked to respiratory centre output (VT/TI) is too rapid to be accounted for by a feed-back mechanism: Saunders (1980) proposed a feed-forward mechanism in which APA, C02/Ate drives ventilation. In a model with the controller equation PE = 6-15 APA, C02/Ate110 acting solely in the feed-forward 8 C. J. ALLEN AND N. L. JONES mode, a simulated increase in PC02 was followed by a small initial increase in ventilation, followed after 30 S by a second rise to a new steady-state ventilation; during this second phase there was a transient rise in arterial PCo, (Saunders, 1980). From the data of the present study we derived the equation: VE = 6-76 APA, C02/Ate - 356 (95 % confidence limits for slope 4-7-8-9, and for intercept - 10-31 to + 3 20), which is remarkably similar to Saunders' (1980) theoretical controller equation and which supports the concept of a feed-forward model. During the second phase (from 30 to 60 s) there was an increase in mean alveolar PCO2 (Fig. 2). This suggests that there may be an additional error signal so that the increase in ventilation may reflect both the rate of rise of Pco2 and an increase in mean Pco2 Understanding of the physiological basis of this model continues to evolve; Band, Cameron & Semple (1969) showed that there are oscillations in arterial blood pH in cats which occur in phase with respiratory oscillations in alveolar Pco,. Infusing CO2 increased not only the amplitude of the oscillation but also the rate of rise of alveolar PCo2* Band et al. (1980) have demonstrated that an immediate increase in both the rate of change of alveolar PCO2 and arterial pH occur following the onset of exercise in man, a finding consistent with our observations. The carotid chemoreceptor is able to respond to oscillations of arterial PCo2, and carotid body stimulation increases inspiratory drive (Band et al. 1970), suggesting that the carotid body may be an important link between APA, C0O2/Ate and VT/TI. It appears that it is not an essential one; Lugliani, Whipp, Seard & Wasserman (1971) were able to demonstrate an increase in ventilation with exercise in carotid body denervated patients. However, the rate of rise in ventilation was considerably slower than it was in patients whose carotid bodies were intact.

The findings of the present study are consistent with the hypothesis that ventilation during exercise is related to CO2 output by a feed-forward control system responding to APA co2/Ate. The mechanisms and pathways mediating this response remain to be elucidated.

C. J. Allen is a Research Fellow of the Medical Research Council of Canada, which also supported this project (grant number MA 4243). The authors thank Geoff Lewis and George Obminski for development of the computer programs and Marilyn Craven, M.D. Ph.D. for her expert critical appraisal of the manuscript.


ALLEN, C. J., JONES, N. L. & KILLIAN, K. J. (1984). Alveolar gas exchange during exercise, a breath-by-breath analysis. Journal of Applied Physiology (in the Press).

ARIELI, R. & VAN LIEW, H. D. (1981). Corrections for the response time and delay of mass spectrometers. Journal of Applied Physiology 51, 1417-1422.

BAND, D. M., CAMERON, I. R. & SEMPLE, S. J. G. (1969). Effect of different methods of CO2 administration on oscillations of arterial pH in the cat. Journal of Applied Physiology 26, 268-273.

BAND, D. M., CAMERON, I. R. & SEMPLE, S. J. G. (1970). The effect on respiration of abrupt changes in carotid artery pH and Pco, in the cat. Journal of Physiology 211, 479-494.

BAND, D. M., WOLFF, C. B., WARD, J., COCHRANE, G. M. & PRIOR, J. (1980). Respiratory oscillation in arterial carbon dioxide tension as a control signal in exercise. Nature 283, 84-85.

BEAVER, W. L., LAMARRA, N. L. & WASSERMAN, K. (1981). Breath-by-breath measurement of true alveolar gas exchange. Journal of Applied Physiology 51, 1662-1675.

BEAVER, W. L., WASSERMAN, K. & WHIPP, B. J. (1973). On-line computer analysis and breathby-breath graphical display of exercise function tests. Journal of Applied Physiology 34, 123-132.


CASABURI, R., WHIPP, B. J., WASSERMAN, K., BEAVER, W. L. & KOYAL, S. N. (1977). Ventilatory and gas-exchange dynamics in response to sinusoidal work. Journal of Applied Physiology 42, 300-311.

COCHRANE, G. M., NEWSTEAD, C. G., NOWELL, R. V., OPENSHAW, P. & WOLFF, C. B. (1982). The rate of rise of alveolar carbon dioxide pressure during expiration in man. Journal of Physiology 333, 17-27.

DAVIES, E. E., HAHN, H. L., SPmo, S. G. & EDWARDS, R. H. T. (1974). A new technique for recording respiratory transients at the start of exercise. Respiration Physiology 20, 69-79.

DEJOURS, P. (1964). Control of respiration in muscular exercise. In Handbook of Physiology, sect.

3, vol. 2. Washington, D.C.: American Physiological Society.

DuBois, A. B., FOWLER, R. C., SOFFER, A. & FENN, W. 0. (1952). Alveolar CO2 measured by expiration into the rapid infra-red gas analyzer. Journal of Applied Physiology 4, 526-534.

FOWLER, W. S. (1948). Lung function studies. II. The respiratory dead space. American Journal of Physiology 154, 405-416.

GRIMBY, G. (1969). Respiration in exercise. Medicine and Science in Sports and Exercise 1, 9-14.

KROGH, A. & LINDHARD, J. (1913). The regulation of respiration and circulation during the initial stages of muscular work. Journal of Physiology 47, 112-136.

LAMB, T. W., ANTHONISEN, N. R. & TENNEY, S. M. (1965). Controlled frequency breathing during muscular exercise. Journal of Applied Physiology 20, 244-248.

LINNARSSON, D. (1974). Dynamics of pulmonary gas exchange at start and end of exercise. Acta physiologica 8candinavica suppl. 415, 1-68.

LUGLIANI, R., WHIPP, B. J., SEARD, C. & WASSERMAN, K. (1971). The effect of carotid body rejection on ventilatory control at rest and during exercise in man. New England Journal of Medicine 285, 1150.

MILIC-EMILI, J. (1982). Recent advances in clinical assessment of control of breathing. Lung 160, 1-17.

MITCHELL, R. R. (1979). Incorporating the gas analyzer response time in gas exchange computations.

Journal of Applied Physiology 47, 1118-1122.

MIYAMOTO, Y., HIURA, T., TAMURA, T., NAKAMURA, T., HIGUCHI, J. & MIKAMI, T. (1982). Dynamics of cardiac, respiratory and metabolic function in men in response to step workload. Journal of Applied Physiology 52, 1198-1208.

NOGUCHI, H., OGUSHI, Y., YOSHIYA, I., ITAKURA, N. & YAMABAYASHI, H. (1982). Breath-by-breath T1co2 and V1, require compensation for transport delay and dynamic response. Journal of Applied Physiology 52, 79-84.

PEARCE, D. H., MILHORN, H. T., HOLLOMAN, G. H. & REYNOLDS, W. J. (1977). Computer based system for analysis of respiratory responses to exercise. Journal of Applied Physiology 42, 968-975.

PHILLIPSON, E. A., BowEs, G., TOWNSEND, E. R., DUFFIN, J. & COOPER, J. (1981a). Carotid chemoreceptors in ventilatory response to changes in venous C02 load. Journal of Applied Physiology 51, 1398-1403.

PHILLIPSON, E. A., BOWES, G., TOWNSEND, E. R., DUFFIN, J. & COOPER, J. (1981b). Role of metabolic C02 production in ventilatory response to steady-state exercise. Journal of Clinical Investigation 68, 768-774.

SAUNDERS, K. B. (1980). Oscillation of arterial CO2 tension in a respiratory model: Some implications for the control of breathing in exercise. Journal of Theoretical Biology 84, 163-179.

SIAFAKAS, N., MORRIS, A. J. R. & PRIME, F. J. (1979). The rate of change of mouth occlusion pressure during exercise. Clinical Science 56, 455-461.

SWANSON, G. (1978). The exercise hyperpnea dilemma. Chest 73, suppl. 277-279.

WESSEL, H. U., STOUT, R. L., BATANIER, C. K. & PAUL, M. H. (1979). Breath-by-breath variations of FRC: effect on V01 and Vco, measured at the mouth. Journal of Applied Physiology 46, 1122-1126.

WHIPP, B. J. & MAHLER, M. (1980). Dynamics of pulmonary gas exchange during exercise. In Pulmonary Ga8 Exchange, vol. II, ed. WEST, J. B. New York, London: Academic Press.

YAMAMOTO, W. S. (1960). Mathematical analysis of the time course of alveolar CO2. Journal of Applied Physiology 15, 215-219.

YAMAMOTO, W. S. & EDWARDS, M. W. (1960). Homeostasis of carbon dioxide during intravenous

Pages:     | 1 ||

Similar works:

«EUROPEAN COMMISSION ENTERPRISE DIRECTORATE GENERAL Industrial affairs III: Consumer goods industries Pharmaceutical products and cosmetics ENTR/III/5711/99 Brussels, 28 November 1999 Annex to the Guide to Good Manufacturing Practice for medicinal products: CERTIFICATION BY A QUALIFIED PERSON AND BATCH RELEASE Discussion in the Working Party June-Nov. 1999 Transmission of draft 3 to the Pharmaceutical September 1999 Committee Transmission of draft 4 to interested parties December 1999 Deadline...»

«Heat Impacts on Occupational Health A Comparison Between Agricultural and Industrial Settings in the Time of Climate Change Sarah Bober Chelsea Ross Miller Gun Charoensiri Suthamma Sa-nguankulchai Devin Harrison Piyada Sutthanusorn Rachel Hickcox Date: March 2, 2012 www.heatisthesilentkiller.weebly.com ABSTRACT Past studies have shown that workers laboring in dangerously hot climates have the potential to experience detrimental effects to both their health and productivity. In the time of...»

«Yummy Benefits! A healthy cooking guide Table of Contents Breakfast: Greek Yogurt with Warm Berry Sauce pg 4 Overnight Oats pg 5 Swiss Oatmeal pg 6 Burritos Three Ways pg 7 Pumpkin Muffins pg 8 Dinner made Easy: Garlic-Citrus Fish pg 10 Spice Crusted Chicken Breast with Mango Salsa pg 11 It’s a Wrap! pg 12 Chicken Tortellini Soup pg 13 Black Bean Turkey Chili pg 14 Turkey Joes pg 15 Italian Summer Soup pg 16 Lime Fish Tacos pg 17 Easy Beef Stir Fry pg 18 Sloppy GI Joes pg 19 Tandoori Style...»

«A Response to Dr. Tommy Mitchell in AIG’s “Get Answers” article: Is Abortion Ever Justifiable? Upon first reading of Dr. Mitchell’s article below, I was filled with a sense of confusion. Upon second reading, my confusion was replaced with grave concern. The first concern that immediately comes to mind is the proposition of a complex and rare medical scenario that is deemed a “no win” situation. Using the example that Dr. Mitchell proposed, I performed a cursory exploration of just...»

«THE IMPACT OF SIMULATED ASTIGMATISM ON FUNCTIONAL MEASURES OF VISUAL PERFORMANCE Sung-Hua Yang B.Optom., MSc. May, 2015 Submitted in fulfilment of the requirements for the degree of Master of Applied Science (Research) Vision and Driving Laboratory School of Optometry and Vision Science Faculty of Health Institute of Health and Biomedical Innovation Queensland University of Technology Keywords Astigmatic blur Astigmatic axis Astigmatic power Visual acuity Reading rates Visual processing speeds...»

«AMERICA'S HEALTHCARE SYSTEM Discussion and Analysis of Problems and Solutions Yuri C. Feynberg, PhD TABLE OF CONTENTS CHAPTER 1 INTRODUCTION Statement of the Problem Purpose of the Study Importance of the Study Scope of the Study Rationale of the Study Definition of Terms Overview of the Study CHAPTER 2 REVIEW OF RELATED LITERATURE Privatization and Healthcare in America Socialization and the Healthcare System Factors Affecting United States Healthcare Market Impacts International Developments...»

«INTERNATIONAL JOURNAL OF IMMUNOPATHOLOGY AND PHARMACOLOGY Vol. 24, no. 4, 817-825 (2011) EDITORIAL ATHEROSCLEROSIS: A CLASSIC INFLAMMATORY DISEASE A. ANOGEIANAKI1, D. ANGELUCCI2, E. CIANCHETTI3, M. D’ALESSANDRO4, G. MACCAURO5, A. SAGGINI6, V. SALINI7, A. CARAFFA8, S. TETÉ9, F. CONTI10, D. TRIPODI9 and Y.B. SHAIK-DASTHAGIRISAHEB11 Physiology Department, School of Medicine, Aristotle University of Thessaloniki, Greece; 1 AnatomoPathology Division, University of Chieti-Pescara, Chieti, Italy;...»

«PACKING Project Guide The 4-H Motto “Learn to Do by Doing” The 4-H Pledge I pledge My Head to clearer thinking, My Heart to greater loyalty, My Hands to larger service, My Health to better living, For my club, my community, and my country. The 4-H Grace (Tune of Auld Lang Syne) We thank thee, Lord, for blessings great on this, our own fair land. Teach us to serve thee joyfully, with head, heart, health and hand.Published by: 4-H Section Alberta Agriculture and Forestry 7000 113 ST RM 200 NW...»

«MOLECULAR MECHANISMS OF LTBP4-RELATED CUTIS LAXA by Chi-Ting Su M.D., School of Medicine, Kaohsiung Medical University, Taiwan, 2003 MPH, University of Pittsburgh, 2012 Submitted to the Graduate Faculty of the Graduate School of Public Health in partial fulfillment of the requirements for the degree of Doctor of Philosophy University of Pittsburgh 2014 UNIVERSITY OF PITTSBURGH GRADUATE SCHOOL OF PUBLIC HEALTH This dissertation was presented by Chi-Ting Su It was defended on April 9, 2014 and...»

«Thomas M. Evans Work: Home: Radiation Transport Group e-mail: tmdelellis@tds.net Oak Ridge National Laboratory phone: (865)748-8190 PO Box 2008 MS 6172 Oak Ridge, TN 37831-6172 e-mail: evanstm@ornl.gov phone: (865)576-3535 Education Atlanta, GA GEORGIA INSTITUTE OF TECHNOLOGY Ph.D. in Nuclear Engineering, March 1997. GPA 4.0. Atlanta, GA GEORGIA INSTITUTE OF TECHNOLOGY M.S. in Health Physics, Medical Physics Option, March 1994. GPA 4.0. Haverford, PA HAVERFORD COLLEGE B.S. in Physics and...»

«Save $150 Register by December 21, 2016 for Early Bird Rates Tempe, Arizona January 20-22, 2017 | Tempe Mission Palms 2017 Clinical Pediatric Hospital Medicine Sponsored by the American Academy of Pediatrics (AAP) and the AAP Section on Hospital Medicine Earn a Maximum of 17.75 AMA PRA Category 1 CreditsTM REGISTER at shop.aap.org/clinicalphm2017 or call toll-free 866/843-2271 WHAT IS THE 2017 CLINICAL PEDIATRIC HOSPITAL MEDICINE COURSE? The Clinical Pediatric Hospital Medicine course is...»

«SPIRIVA® RESPIMAT® 2.5 microgram, solution for inhalation United Kingdom tiotropium SUMMARY OF PRODUCT CHARACTERISTICS 1. NAME OF THE MEDICINAL PRODUCT Spiriva Respimat 2.5 microgram, solution for inhalation 2. QUALITATIVE AND QUANTITATIVE COMPOSITION The delivered dose is 2.5 microgram tiotropium per puff (2 puffs comprise one medicinal dose) and is equivalent to 3.124 microgram tiotropium bromide monohydrate. The delivered dose is the dose which is available for the patient after passing...»

<<  HOME   |    CONTACTS
2016 www.dissertation.xlibx.info - Dissertations, online materials

Materials of this site are available for review, all rights belong to their respective owners.
If you do not agree with the fact that your material is placed on this site, please, email us, we will within 1-2 business days delete him.