Kinetics of pulmonary uptake of serotonin during exercise in dogs

1996 ◽  
Vol 80 (1) ◽  
pp. 30-46 ◽  
Author(s):  
J. Dupuis ◽  
C. A. Goresky ◽  
J. L. Rouleau ◽  
G. G. Bach ◽  
A. Simard ◽  
...  
Keyword(s):  
Blood Flow ◽  
Surface Area ◽  
Blood Volume ◽  
Extravascular Lung Water ◽  
Central Blood Volume ◽  
Lung Water ◽  
Pulmonary Uptake ◽  
Average Proportion ◽  
Area Product ◽  
Kinetics Of

The multiple indicator-dilution technique was employed in the exercising dog to evaluate the effect of increasing activity on the pulmonary extraction and kinetics of removal of tracer 3H-labeled serotonin (5-HT) and on the measured central blood volume and tracer-accessible extravascular lung water. 51Cr-labeled red blood cells, 125I-labeled albumin, and 14C-labeled 1,8-octanediol were injected with labeled 5-HT at rest and at two increasing levels of exercise (lower and higher in 9 dogs). Blood flow approximately tripled at the highest level of exercise, and the central blood volume increased linearly with increasing blood flow. The tracer-accessible extravascular lung water increased in the transition from rest to low-level exercise and stabilized at an average proportion of 0.85 of the gravimetric extravascular lung water at the higher values of blood flow. The average labeled 5-HT extraction at rest was 42 +/- 11%, and this slowly decreased with increase in flow. The calculated permeability-surface area product for 5-HT increased approximately directly with increasing blood flow. We conclude that exercise results in an increase in the central blood volume that is accompanied by an increase in the tracer-accessible extravascular lung water (lung tissue recruitment) over low exercise levels, with no change at higher levels of exercise, and that the pulmonary capillary surface area subserving 5-HT uptake increases almost linearly with flow over the range of flows attained.

Pulmonary angiotensin-converting enzyme substrate hydrolysis during exercise

1992 ◽  
Vol 72 (5) ◽  
pp. 1868-1886 ◽  
Author(s):  
J. Dupuis ◽  
C. A. Goresky ◽  
J. W. Ryan ◽  
J. L. Rouleau ◽  
G. G. Bach
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Surface Area ◽  
Blood Volume ◽  
Extravascular Lung Water ◽  
Central Blood Volume ◽  
Converting Enzyme ◽  
Lung Water ◽  
Vascular Surface ◽  
Enzyme Substrate ◽  
Exercise Induced

We examined exercise-induced changes in indicator-dilution estimates of the angiotensin-converting enzyme first-order kinetic parameter, the ratio of a normalized maximal enzymatic conversion rate to the Michaelis constant (Amax/Km), which, under stable enzymatic conditions, will vary with the pulmonary vascular surface area accessible to vascular substrate, the extravascular lung water (an index of the proportion of lung tissue perfused), and the central blood volume (from pulmonary trunk to aorta). Experiments were performed in 10 mongrel dogs at rest and through two increasing levels of treadmill exercise, with the use of two vascular space tracers (labeled erythrocytes and albumin), a water space tracer ([1,8–14C]-octanediol), and a vascular endothelium surface area marker, benzoyl-Phe-Gly-Pro ([3H]BPGP), which is a pharmacologically inactive angiotensin-converting enzyme substrate. The exercise-induced increase in cardiac output was accompanied by a linear increase in central blood volume, and dilutional extravascular lung water rapidly increased to an asymptotic proportion close to 100% of postmortem vascular lung water. There was an average 55% [3H]BPGP hydrolysis, which did not vary with flow, and the computed Amax/Km increased linearly with exercise. We conclude that exercise results in complete lung tissue recruitment and increases the pulmonary vascular surface area available for BPGP hydrolysis linearly with flow, so that pulmonary vascular recruitment continues after full tissue recruitment.

scholarly journals Quantitative Measurement of Cerebral Blood Flow and Cerebral Blood Volume after Cerebral Ischaemia

1986 ◽  
Vol 6 (3) ◽  
pp. 338-341 ◽  
Author(s):  
Nicholas V. Todd ◽  
Piero Picozzi ◽  
H. Alan Crockard
Keyword(s):  
Blood Flow ◽  
Surface Area ◽  
Blood Volume ◽  
Quantitative Measurement ◽  
Cerebral Blood Volume ◽  
Vessel Occlusion ◽  
Permeability Surface ◽  
Area Product ◽  
Hydrogen Clearance ◽  
Clearance Technique

CBF obtained by the hydrogen clearance technique and cerebral blood volume (CBV) calculated from the [14C]dextran space were measured in three groups of rats subjected to temporary four-vessel occlusion to produce 15 min of ischaemia, followed by 60 min of reperfusion. In the control animals, mean CBF was 93 ± 6 ml 100 g−1 min−1, which fell to 5.5 ± 0.5 ml 100 g−1 min−1 during ischaemia. There was a marked early postischaemic hyperaemia (262 ± 18 ml 100g−1 min−1), but 1 h after the onset of ischaemia, there was a significant hypoperfusion (51 ± 3 ml 100 g−1 min−1). Mean cortical dextran space was 1.58 ± 0.09 ml 100 g−1 prior to ischaemia. Early in reperfusion there was a significant increase in CBV (1.85 ± 0.24 ml 100 g−1) with a decrease during the period of hypoperfusion (1.33 ± 0.03 ml 100 g−1). Therefore, following a period of temporary ischaemia, there are commensurate changes in CBF and CBV, and alterations in the permeability–surface area product at this time may be due to variations in surface area and not necessarily permeability.

Effects of prolonged surgical trauma on the extravascular lung water and central blood volume in the dog

1986 ◽  
Vol 30 (4) ◽  
pp. 309-313 ◽  
Author(s):  
C. Frostell ◽  
H. Blomqvist ◽  
G. Hedenstierna ◽  
R. Pieper ◽  
I. Halbig
Keyword(s):  
Blood Volume ◽  
Extravascular Lung Water ◽  
Surgical Trauma ◽  
Central Blood Volume ◽  
Lung Water

Use of norepinephrine uptake to measure lung capillary recruitment with exercise

1990 ◽  
Vol 68 (2) ◽  
pp. 700-713 ◽  
Author(s):  
J. Dupuis ◽  
C. A. Goresky ◽  
C. Juneau ◽  
A. Calderone ◽  
J. L. Rouleau ◽  
...  
Keyword(s):  
Surface Area ◽  
Lung Tissue ◽  
Extravascular Lung Water ◽  
Lung Water ◽  
Lung Weight ◽  
Capillary Recruitment ◽  
Multiple Indicator Dilution ◽  
Vascular Space ◽  
Permeability Surface ◽  
Area Product

We used the multiple indicator-dilution technique with norepinephrine, a vascular endothelium surface marker, to study the pulmonary vascular changes in awake exercising dogs. The vascular space tracers, labeled erythrocytes and albumin, and a water space tracer, 1,8-octanediol, were injected with the norepinephrine, and right atrium-aortic root dilution curves were obtained in nine dogs, at rest and at two increasing levels of exercise. Extravascular lung water multiple tracer dilutional estimates increased with flow and rapidly approached a maximal asymptotic value representing 75% of the postmortem lung weight. The ratio of the extravascular lung water measured in this way to that measured gravimetrically also increased, to reach an asymptotic proportion of close to 100%. The transit time-defined central vascular space increased linearly with flow; the ratio of lung tissue space to lung vascular space, therefore, decreased with increasing flow. The mean tracer upslope norepinephrine extractions at rest and at the two levels of exercise were 17 +/- 1.2, 14 +/- 0.8, and 15 +/- 0.8% (SE). With the use of the Crone approximation, we computed permeability-surface area products for norepinephrine; these increased linearly with flow. If permeability does not change, the increase in the permeability-surface area product with flow can be attributed to capillary recruitment. We conclude that when all lung tissue has become accessible to 1,8-octanediol delivered via the perfused vascular space, there is nevertheless further recruitment, with increase in flow, of vascular surface that can extract norepinephrine.

Determination of Central Blood Volume and Extravascular Lung Water

1987 ◽  
Vol 35 (01) ◽  
pp. 53-56 ◽  
Author(s):  
J. Böck ◽  
A. Hoeft ◽  
H. Korb ◽  
R. de Vivie ◽  
G. Hellige
Keyword(s):  
Blood Volume ◽  
Extravascular Lung Water ◽  
Central Blood Volume ◽  
Lung Water

Estimation of extravascular lung water in humans with use of 2H2O: effect of blood flow and central blood volume

1994 ◽  
Vol 76 (5) ◽  
pp. 1868-1875 ◽  
Author(s):  
C. J. Wallin ◽  
L. G. Leksell
Keyword(s):  
Blood Volume ◽  
Extravascular Lung Water ◽  
Human Study ◽  
Repeated Measurements ◽  
Central Blood Volume ◽  
Lung Water ◽  
Double Indicator Dilution ◽  
On Line ◽  
End Tidal ◽  
Spontaneously Breathing

In the present human study we evaluated a newly developed double-indicator-dilution densitometric system for the estimation of cardiac output (Q), central blood volume (CBV), and extravascular lung water (EVLW) by using indocyanine green and heavy water (2H2O) as indicators. Eighteen cardiopulmonary healthy patients scheduled for abdominal surgery were studied. A routine anesthesia procedure was used [thiopental (3–5 mg/kg), N2O (inspired fraction of O2 = 0.4), and isoflurane (end tidal 0.5–1.5%)]. Q, CBV, and EVLW were measured at seven defined data collection points: awake, anesthetized spontaneously breathing, apneic, mechanically ventilated with and without positive end-expiratory pressure, post-operatively anesthetized, and postoperatively awake. During the whole study EVLW (3.8 +/- 0.9 ml/kg) was stable in the presence of large fluctuations in Q (2.5–10.1 l/min) and CBV (0.8–2.4 l). We concluded that the method is versatile and of low invasiveness, allowing reliable on-line Q and EVLW data for repeated measurements in the clinical setting.

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