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At least 1,243 records · Page 69Linked to original sources
PubMed2006

Postoperative effects of anesthesia and surgery on resting energy expenditure in horses as measured by indirect calorimetry.

In this study, we aimed to define the effects of anesthesia and surgery on the resting energy expenditure of horses in experimental conditions. Six horses were used in a longitudinal study with 2 study periods: before and after anesthesia and surgery. Every horse underwent a standard 90-min ventral midline exploratory laparotomy. Oxygen uptake (VO2) and carbon dioxide output (VCO2) were measured, with the use of a closed-circuit spirometry system, on 5 consecutive days immediately before and after the surgery. In 3 consecutive 5-min periods each day, the expired air was collected in a Collins spirometer. Samples of the expired gas were drawn from the spirometer through a drying column into O2 and CO2 analyzers. Resting energy expenditure was calculated as [(VO2 STPD*3.94) + (VCO2 STPD*1.11)]*1.44. This study showed that anesthesia and ventral midline exploratory laparotomy in experimental conditions increase the postoperative caloric demand in horses by an average of 1.0 Mcal/d, which represents approximately a 10% increase (P = 0.03). Additional studies in critically ill horses after surgery are needed to determine their caloric needs and to optimize their nutritional management.

Anesthesia↗
PubMed1990

Calorimetry as an analytical tool for germination tests of plant seeds.

Heat evolution associated with the germination of radish seeds was quantitatively studied in a calorimeter. After incubation at 30 degrees C for 20 to 50 h, the total heat evolved was correlated with the length of buds and roots, and with the increase in weight of the germinating seeds. By regression analysis, the heat produced per unit of bud and root growth was found to be a1 = 0.5723 J/mm of bud and a2 = 0.7093 J/mm of root, respectively, with a correlation coefficient of 0.9577. From these results we conclude that the calorimetric determination of the heat generated during germination is a valid reflection of the germination activity of radish seeds. Our calorimetric method is applicable to the quantitative investigation of the viable activity of plant seeds.

Body Temperature Regulation↗
PubMed1989

[Use of direct calorimetry for continuously following the course of experimental infections in the mouse].

To obtain information about early symptoms of infection measurements of heat production were performed in experimentally infected animals. As a model Mengo virus-infected mice were used. Construction and physical properties of the flow calorimeter device are described. Fever was not detected by method used. However, deviations from normal behaviour of the animals were demonstrated as a result of the relationship between motoric activity and heat produced. Furthermore, the method may be particularly useful for the determination of the exact time of death, which is of interest for mathematical modelling of survival data (RECKNAGEL et al. 1986; GUTHKE et al. 1987; SUHNEL und VECKENSTEDT 1989).

Animals↗
PubMed1989

[Study of the effect of etoposide on the fluidity of dipalmitoylphosphatidylcholine liposome by differential scanning calorimetry and Raman spectroscopy].

The interaction of the anticancer drug, etoposide (VP16-213), with DPPC bilayer vesicles was investigated by DSC and Laser Raman techniques. The results present the fact that the incorporation of VP16-213 into aqueous dispersion of DPPC not only shifted the temperatures of phase transition towards higher value but also broadened the half-height width. The Raman spectra of the DPPC liposome in the C-H symmetric strech vibration lost intensity near 2850cm-1, therefore, it can be predicted that VP16-213 is localized at C1-C9 methylene region of the bilayer, which leads to the increase of the membrane's regularity and the decrease of its fluidity.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1988

Stopped-flow calorimetry of myosin ATP hydrolysis: an implication of chemomechanical energy transduction.

Measurements were made of heat production in the pre-steady state phase of ATP hydrolysis by myosin subfragment 1 using an improved stopped-flow calorimeter. This instrument can measure temperature changes as small as 3 X 10(-4) K with a thermal response time of less than 10 ms. When SF-1 was mixed with ATP at 0 degrees C, there was a fairly rapid heat absorbing phase (rate constant, 20-25 s-1 at pH 8) after a burst of heat production was complete within the dead time of the instrument (10 ms). Then followed a phase of very slow heat production with a heat rate of 7 kJ/mol/s. This result indicates that the ATP binding to SF-1 is an exothermic process whereas the subsequent isoenergetic splitting of ATP on the myosin site is endothermic. Thus, a decrease in the internal energy drives the ATP binding which may be regarded as the chemical energy trapping process. By contrast, the myosin intermediate with hydrolysis products (ADP + Pi) is stabilized by a large increase in entropy. In energy transduction by myosin/actin system of muscle, therefore, switching of chemical energy into a form available for mechanical work would be a transition from a low entropy to a high entropy state of weakly actin binding conformations of myosin.

Adenosine Triphosphatases↗