Endotracheal intubation influences respiratory water loss during heat stress in young lambs

1995 ◽  
Vol 79 (3) ◽  
pp. 801-804 ◽  
Author(s):  
K. Hammarlund ◽  
T. Norsted ◽  
T. Riesenfeld ◽  
G. Sedin
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Heat Stress ◽  
Body Temperature ◽  
Water Loss ◽  
Radiative Heat ◽  
Carbon Dioxide Production ◽  
Gas Analysis ◽  
Warm Environment ◽  
Flow Through

To study the effect of intubation on respiratory water loss (RWL) during heat stress, 10 young nonsedated lambs were exposed to radiative heat stress both when intubated and when not. RWL, oxygen consumption (VO2), and carbon dioxide production were monitored continuously by using a flow-through system with a mass spectrometer for gas analysis. When the lambs were not intubated, heat stress caused RWL to increase by 218%, whereas VO2 and body temperature remained unchanged. When the lambs were intubated, heat stress caused RWL to increase by 131% and VO2 to increase by 36%. On extubation during heat stress, RWL increased by 117 +/- 48% (standard error of the estimate) of the preextubation value and body temperature started to fall. This study shows that intubation reduces the ability of the lamb to increase RWL and heat loss during heat stress in a warm environment, possibly as an effect of exclusion of the nose and a reduction in dead space. After extubation, RWL increases markedly, a finding that might also be valid for intubated infants.

Flow-through Respirometry: The Equations

2018 ◽  
pp. 94-100
Author(s):  
John R. B. Lighton
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Water Vapor ◽  
Carbon Dioxide Production ◽  
System P ◽  
Flow Through

This chapter demystifies respirometry equations, showing how they can be derived using a simple mental trick: focusing the analysis on the principal gas that is neither consumed nor produced by animals. The effect of dilution of oxygen by carbon dioxide, the enrichment of carbon dioxide by the consumption of oxygen, and the effects of water vapor on the concentrations of both gases are described and quantified. A system of eight equations is derived that allow oxygen consumption and carbon dioxide production to be calculated in practically any feasible flow-through respirometry system.

Thermoregulatory responses of dystrophic hamsters to changes in ambient temperatures

1985 ◽  
Vol 63 (9) ◽  
pp. 1145-1150 ◽  
Author(s):  
M. Desautels ◽  
R. A. Dulos ◽  
J. A. Thornhill
Keyword(s):  
Carbon Dioxide ◽  
Adipose Tissue ◽  
Oxygen Consumption ◽  
Body Temperature ◽  
Metabolic Activity ◽  
Carbon Dioxide Production ◽  
Ambient Temperatures ◽  
Brown Adipose ◽  
Lower Temperature ◽  
Do So

The ability of dystrophic hamsters to maintain their body temperature despite abnormal muscle and brown adipose tissue, two organs involved in thermoregulation, was evaluated. Dystrophic hamsters (CHF 146) between the ages of 30 and 160 days kept at 21 °C had core (rectal) temperatures (TR) that were 0.5–1.5 °C lower than Golden Syrian controls. The reduced core temperatures of dystrophic hamsters were unlikely the result of an incapacity to generate heat since the dystrophic hamsters were able to maintain their TRs during 3 h of acute cold stress (4 °C) and to adapt to prolonged cold exposure. However, TRs of cold-acclimated dystrophic hamsters were still 1 °C below TRs of cold-acclimated control animals. By contrast, increasing the ambient temperature raised TRs of both normal and dystrophic hamsters. When kept at 32 °C overnight, the TRs of dystrophic hamsters remained significantly below those of control animals. When heat-exposed dystrophic hamsters were returned to 21 °C, their TRs returned to values significantly lower than those of control hamsters. Thus, dystrophic hamsters showed a capacity to thermoregulate, like control hamsters, but appeared to do so at a lower temperature. The reduced core temperatures of dystrophic hamsters kept at 21 °C cannot be explained by a reduction in metabolic activity since newborns and 30- and 140-day-old dystrophic hamsters had rates of oxygen consumption [Formula: see text] and carbon dioxide production [Formula: see text] that were similar to those of controls. These results suggest that the thermoregulatory set point may be altered in dystrophic hamsters.

scholarly journals EFFECT OF INTRAOSSEOUS INTRODUCTION OF SELENIUM/ARABINOGALACTAN NANOGLYCOCONJUGATE ON THE MAIN INDICATORS OF PRIMARY METABOLISM IN CONSOLIDATION OF BONE FRACTURE

2016 ◽  
Vol 1 (4) ◽  
pp. 104-108 ◽  
Author(s):  
Родионова ◽  
Lyubov Rodionova ◽  
Сухов ◽  
Boris Sukhov ◽  
Самойлова ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Body Temperature ◽  
Carbon Dioxide Production ◽  
Control Group ◽  
Elemental Selenium ◽  
Primary Metabolism ◽  
Femoral Bone ◽  
Surgical Wound ◽  
Experimental Group

The research was carried out on 9rabbits (males) of Chinchilla breed with modeling of standard perforating fracture of femoral bone. We performed intraosseous introduction of nanocomposite elemental selenium and heteropolysaccharide arabinogalactan 50mg Se/kg to individuals of experimental group (n=3) and NaCl 0,9% to individuals of control group (n=6). It was established that local intraosseous introduction of the nanocomposite with perforated fracture model did not affect basal metabolic indicators (body temperature, oxygen consumption, carbon dioxide production), but boosted the metabolic processes in the area of the surgical wound from the 9th to 21st days. It proves the bioavailability of the drug and the possibility of creating a local depot of selenium using a nanocomposite.

Validating Flow-through Respirometry

2018 ◽  
pp. 170-176
Author(s):  
John R. B. Lighton
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Carbon Dioxide Production ◽  
Hydrocarbon Gases ◽  
Yield Information ◽  
Consumption Rates ◽  
Recovery Technique ◽  
Flow Through ◽  
Alcohol Recovery ◽  
Gas Flame

This chapter describes methods for validating the measurements made using flow-through respirometry. These methods include the injection of nitrogen at a known flow rate into a respirometry system; burning a small flame of ethanol or methanol at a rate measured by weighing the lamp (often called “alcohol recovery”); and burning hydrocarbon gases such as methane, ethane, or propane. The first two techniques yield information on absolute oxygen consumption rates; the gas flame technique yields information on ratios between oxygen consumption and carbon dioxide production, as does the alcohol recovery technique. Full practical details including all relevant equations are given.

scholarly journals Loss of prokineticin receptor 2 signaling predisposes mice to torpor

2008 ◽  
Vol 294 (6) ◽  
pp. R1968-R1979 ◽  
Author(s):  
Preeti H. Jethwa ◽  
Helen I'Anson ◽  
Amy Warner ◽  
Hayden M. Prosser ◽  
Michael H. Hastings ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Locomotor Activity ◽  
Energy Balance ◽  
Body Temperature ◽  
Transgenic Mice ◽  
Food Deprivation ◽  
Carbon Dioxide Production ◽  
Dark Phase ◽  
Torpor Bouts

The genes encoding prokineticin 2 polypeptide (Prok2) and its cognate receptor ( Prokr2/ Gpcr73l1) are widely expressed in both the suprachiasmatic nucleus and its hypothalamic targets, and this signaling pathway has been implicated in the circadian regulation of behavior and physiology. We have previously observed that the targeted null mutation of Prokr2 disrupts circadian coordination of cycles of locomotor activity and thermoregulation. We have now observed spontaneous but sporadic bouts of torpor in the majority of these transgenic mice lacking Prokr2 signaling. During these torpor bouts, which lasted for up to 8 h, body temperature and locomotor activity decreased markedly. Oxygen consumption and carbon dioxide production also decreased, and there was a decrease in respiratory quotient. These spontaneous torpor bouts generally began toward the end of the dark phase or in the early light phase when the mice were maintained on a 12:12-h light-dark cycle and persisted when mice were exposed to continuous darkness. Periods of food deprivation (16–24 h) induced a substantial decrease in body temperature in all mice, but the duration and depth of hypothermia was significantly greater in mice lacking Prokr2 signaling compared with heterozygous and wild-type littermates. Likewise, when tested in metabolic cages, food deprivation produced greater decreases in oxygen consumption and carbon dioxide production in the transgenic mice than controls. We conclude that Prokr2 signaling plays a role in hypothalamic regulation of energy balance, and loss of this pathway results in physiological and behavioral responses normally only detected when mice are in negative energy balance.

Contribution of gular flutter to evaporative cooling in Japanese quail

1976 ◽  
Vol 40 (4) ◽  
pp. 521-524 ◽  
Author(s):  
W. W. Weathers ◽  
D. C. Schoenbaechler
Keyword(s):  
Oxygen Consumption ◽  
Heat Stress ◽  
Body Temperature ◽  
Japanese Quail ◽  
Water Loss ◽  
Evaporative Water ◽  
Coturnix Coturnix ◽  
Air Temperatures ◽  
Acute Heat Stress ◽  
Cooling Mechanism

Oxygen consumption, body temperature (Tb), and evaporative water loss (mwe) were determined in intact Japanese quail (Coturnix coturnix), and in quail in which the hyoid musculature responsible for gular flutter had been surgically transected several days prior to study. Abolishing gular flutter reduced total mwe by an average of 20% at air temperatures (Ta) above 40 degrees C. Treated birds developed a significantly greater degree of hyperthermia during acute heat stress than the controls and, unlike the controls, were unable to maintain Tb less than Ta above 40 degrees C. These data demonstrate that gular flutter represents a significant cooling mechanism in heat-stressed quail.

Metabolism during normoxia, hyperoxia, and recovery in newborn rats

1992 ◽  
Vol 70 (3) ◽  
pp. 408-411 ◽  
Author(s):  
Peter B. Frappell ◽  
Andrea Dotta ◽  
Jacopo P. Mortola
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Carbon Dioxide Production ◽  
Oxygen Availability ◽  
Aerobic Metabolism ◽  
Newborn Rats ◽  
Ambient Temperatures ◽  
Positive Effects

Aerobic metabolism (oxygen consumption, [Formula: see text], and carbon dioxide production, [Formula: see text]) has been measured in newborn rats at 2 days of age during normoxia, 30 min of hyperoxia (100% O2) and an additional 30 min of recovery in normoxia at ambient temperatures of 35 °C (thermoneutrality) or 30 °C. In normoxia, at 30 °C [Formula: see text] was higher than at 35 °C. With hyperoxia, [Formula: see text] increased in all cases, but more so at 30 °C (+20%) than at 35 °C (+9%). Upon return to normoxia, metabolism readily returned to the prehyperoxic value. The results support the concept that the normoxic metabolic rate of the newborn can be limited by the availability of oxygen. At temperatures below thermoneutrality the higher metabolic needs aggravate the limitation in oxygen availability, and the positive effects of hyperoxia on [Formula: see text] are therefore more apparent.Key words: neonatal respiration, oxygen consumption, thermoregulation.

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