scholarly journals Optical measurement of isolated canine lung filtration coefficients at normal hematocrits

1997 ◽  
Vol 83 (6) ◽  
pp. 1976-1985 ◽  
Author(s):  
Joseph W. Klaesner ◽  
N. Adrienne Pou ◽  
Richard E. Parker ◽  
Charlene Finney ◽  
Robert J. Roselli
Keyword(s):  
Surface Area ◽  
Optical Measurement ◽  
Venous Pressure ◽  
Gravimetric Method ◽  
Volume Changes ◽  
Multiple Indicator Dilution ◽  
Permeability Surface ◽  
Multiple Indicator ◽  
Area Product ◽  
Filter Cartridge

Klaesner, Joseph W., N. Adrienne Pou, Richard E. Parker, Charlene Finney, and Robert J. Roselli. Optical measurement of isolated canine lung filtration coefficients at normal hematocrits. J. Appl. Physiol. 83(6): 1976–1985, 1997.—In this study, lung filtration coefficient ( K fc) values were measured in eight isolated canine lung preparations at normal hematocrit values using three methods: gravimetric, blood-corrected gravimetric, and optical. The lungs were kept in zone 3 conditions and subjected to an average venous pressure increase of 10.24 ± 0.27 (SE) cmH2O. The resulting K fc(ml ⋅ min−1 ⋅ cmH2O−1 ⋅ 100 g dry lung wt−1) measured with the gravimetric technique was 0.420 ± 0.017, which was statistically different from the K fc measured by the blood-corrected gravimetric method (0.273 ± 0.018) or the product of the reflection coefficient (ςf) and K fc measured optically (0.272 ± 0.018). The optical method involved the use of a Cellco filter cartridge to separate red blood cells from plasma, which allowed measurement of the concentration of the tracer in plasma at normal hematocrits (34 ± 1.5). The permeability-surface area product was measured using radioactive multiple indicator-dilution methods before, during, and after venous pressure elevations. Results showed that the surface area of the lung did not change significantly during the measurement of K fc. These studies suggest that ςf K fccan be measured optically at normal hematocrits, that this measurement is not influenced by blood volume changes that occur during the measurement, and that the optical ςf K fcagrees with the K fc obtained via the blood-corrected gravimetric method.

Effect of perfusate hematocrit on urea permeability-surface area in isolated dog lung

1986 ◽  
Vol 61 (4) ◽  
pp. 1383-1387 ◽  
Author(s):  
R. E. Parker ◽  
R. J. Roselli ◽  
F. R. Haselton ◽  
T. R. Harris
Keyword(s):  
Surface Area ◽  
Left Lung ◽  
Multiple Indicator Dilution ◽  
Urea Permeability ◽  
Permeability Surface ◽  
Wide Range ◽  
Multiple Indicator ◽  
Area Product ◽  
Erythrocyte Trapping ◽  
Reference Tracer

Seven dog lower left lung lobes were statically inflated and perfused at a constant rate for each lobe with a perfusate in which the hematocrit was altered over a wide range. The permeability-surface area of urea was calculated from multiple indicator dilution curves using two separate injectates for each hematocrit level. One injectate contained only 125I-albumin as the vascular reference tracer and the other contained both 51Cr-erythrocytes and 125I-albumin as the vascular reference tracers; both contained [14C]urea as the permeating tracer. The results strongly indicate that the phenomenon of “erythrocyte trapping” of urea does not affect the calculation of urea permeability-surface area product provided the appropriate albumin-erythrocyte composite reference tracer is utilized in its calculation.

Endothelial adenosine transporter characterization in perfused guinea pig hearts

2000 ◽  
Vol 279 (4) ◽  
pp. H1502-H1511 ◽  
Author(s):  
Lisa M. Schwartz ◽  
Thomas R. Bukowski ◽  
James D. Ploger ◽  
James B. Bassingthwaighte
Keyword(s):  
Guinea Pig ◽  
Surface Area ◽  
Cell Types ◽  
Maximal Velocity ◽  
Passive Transport ◽  
Multiple Indicator Dilution ◽  
Luminal Membrane ◽  
Permeability Surface ◽  
Multiple Indicator

Adenosine (Ado), a smooth muscle vasodilator and modulator of cardiac function, is taken up by many cell types via a saturable transporter, blockable by dipyridamole. To quantitate the influences of endothelial cells in governing the blood-tissue exchange of Ado and its concentration in the interstitial fluid, one must define the permeability-surface area products ( PS) for Ado via passive transport through interendothelial gaps [ PS g(Ado)] and across the endothelial cell luminal membrane ( PS ecl) in their normal in vivo setting. With the use of the multiple-indicator dilution (MID) technique in Krebs-Ringer perfused, isolated guinea pig hearts (preserving endothelial myocyte geometry) and by separating Ado metabolites by HPLC, we found permeability-surface area products for an extracellular solute, sucrose, via passive transport through interendothelial gaps [ PS g(Suc)] to be 1.9 ± 0.6 ml · g−1 · min−1( n = 16 MID curves in 4 hearts) and took PS g(Ado) to be 1.2 times PS g(Suc). MID curves were obtained with background nontracer Ado concentrations up to 800 μm, partially saturating the transporter and reducing its effective PS ecl for Ado. The estimated maximum value for PS ecl in the absence of background adenosine was 1.1 ± 0.1 ml · g−1 · min−1 [maximum rate of transporter conformational change to move the substrate from one side of the membrane to the other (maximal velocity; V max) times surface area of 125 ± 11 nmol · g−1 · min−1], and the Michaelis-Menten constant ( K m) was 114 ± 12 μM, where ± indicates 95% confidence limits. Physiologically, only high Ado release with hypoxia or ischemia will partially saturate the transporter.

Endothelial extraction of tracer water is independent of temperature in dog lungs

1986 ◽  
Vol 250 (6) ◽  
pp. H1017-H1021
Author(s):  
F. P. Chinard ◽  
W. O. Cua
Keyword(s):  
Surface Area ◽  
Evans Blue ◽  
Indicator Dilution ◽  
Appearance Time ◽  
Flow Rates ◽  
Multiple Indicator Dilution ◽  
Permeability Surface ◽  
Multiple Indicator ◽  
Dilution Experiments ◽  
Dependent Flow

Diffusion and viscosity-dependent flow rates generally decrease with decrease of temperature in biological systems. We have examined the extraction (Ec) of tracer water in isolated dog lungs perfused near 37 degrees C and near 15 degrees C with multiple-indicator dilution experiments. If Ec were barrier limited, Ec should be less at lower temperatures. Two runs at 37 degrees C were followed by two runs at 15 degrees C. Evans blue (T-1824) was used as vascular reference, and tritium oxide (THO) was used as water tracer. Values of Ec were based on the ratio of the areas under the two indicator curves from appearance time to time of peak of T-1824. Values for permeability-surface area (PS) products were calculated from the classical Crone relationship in 14 experiments with a total of 56 runs. Neither Ec nor PS decreased with temperature. Instead, modest but statistically significant increases were found. We conclude that the extraction of tracer water in these preparations is not barrier limited.

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.

scholarly journals A comparison of ascorbate and glucose transport in the heart

1985 ◽  
Vol 249 (1) ◽  
pp. H141-H149 ◽  
Author(s):  
J. B. Bassingthwaighte ◽  
J. T. Kuikka ◽  
I. S. Chan ◽  
T. Arts ◽  
R. S. Reneman
Keyword(s):  
Surface Area ◽  
Indicator Dilution ◽  
Cell Permeability ◽  
Intracellular Space ◽  
Molecular Weights ◽  
Multiple Indicator Dilution ◽  
Modeling Analysis ◽  
Permeability Surface ◽  
Spatially Distributed ◽  
Multiple Indicator

Multiple indicator-dilution experiments were done to compare the transcapillary exchange of tracer amounts of L-[14C]ascorbate and D-[3H]glucose (against an intravascular reference 131I-albumin) in Ringer-perfused (5 mM glucose) isolated rabbit hearts. The indicator-dilution curves for the two were virtually superimposed over the first 40-80 s. Estimates of the capillary permeability-surface area products, PSc, were the same, 2.3 +/- 0.7 (SD) ml X g-1 X min-1 (n = 18), in accord with the coincidence of their instantaneous extractions. The similarity of glucose and ascorbate permeabilities is explained by the similarity in molecular weights and passive diffusivity, their lipophobic nature, and the paucity of carrier-mediated endothelial transport for either molecule. The data were analyzed via a model composed of aggregates of spatially distributed capillary-tissue units (capillary blood, interstitium, myocytes) accounting for the heterogeneity of regional flows. The interstitial volumes in this preparation are enlarged, 0.30 +/- 0.04 ml/g. There is substantial entry into myocardial cells, the cell permeability-surface area products being approximately 2-3 ml X g-1 X min-1 for ascorbate and glucose. The estimated volumes of interstitial and intracellular space, 0.30 and 0.47 ml X g-1 X min-1, reflect interstitial edema and are very close to measured values, giving reassurance concerning the methods of modeling analysis.

Effects of flow, perfusion pressure, and oxygen consumption on cardiac capillary exchange

1995 ◽  
Vol 78 (4) ◽  
pp. 1350-1359 ◽  
Author(s):  
D. F. Cousineau ◽  
C. A. Goresky ◽  
C. P. Rose ◽  
A. Simard ◽  
A. J. Schwab
Keyword(s):  
Oxygen Consumption ◽  
Surface Area ◽  
Coronary Flow ◽  
Myocardial Oxygen Consumption ◽  
Perfusion Pressure ◽  
Multiple Indicator Dilution ◽  
Permeability Surface ◽  
Anesthetized Dogs ◽  
Capillary Exchange ◽  
Area Product

The roles of blood flow, local oxygen consumption, and perfusion pressure on cardiac transcapillary exchange were characterized in closed-chest anesthetized dogs by use of the multiple-indicator dilution technique. Occlusion of the carotid arteries or injection of dipyridamole increased coronary flow to significantly higher values compared with a group of animals in a basal state obtained in a previous study. Carotid occlusion resulted in a significant increase in perfusion pressure and myocardial oxygen consumption, whereas these two variables were significantly reduced after dipyridamole. For the whole group of animals, the capillary permeability-surface area product for sucrose increased with coronary flow, which appeared to be the important controller for this microcirculatory exchange parameter. Perfusion pressure and myocardial oxygen consumption also regulated permeability-surface area product values, although to a lesser extent than flow. The heterogeneity of transit times in the capillaries was reduced at high coronary flow values, despite large differences in the cardiac utilization of oxygen. The data suggest that cardiac capillary exchange responds mostly to hemodynamic changes originating at the precapillary level.

Uptake of lactate by the liver: effect of red blood cell carriage

2000 ◽  
Vol 278 (5) ◽  
pp. G775-G788 ◽  
Author(s):  
Carl A. Goresky ◽  
Glen G. Bach ◽  
André Simard ◽  
Andreas J. Schwab ◽  
Adelar Bracht
Keyword(s):  
Lactate Metabolism ◽  
Total Flow ◽  
Total Flow Rate ◽  
Multiple Indicator Dilution ◽  
Permeability Surface ◽  
Anesthetized Dogs ◽  
Multiple Indicator ◽  
Dilution Experiments ◽  
Area Product ◽  
Rate Limiting

Multiple-indicator dilution experiments with labeled lactate were performed in the livers of anesthetized dogs. A mixture of51Cr-labeled erythrocytes, [3H]sucrose, andl-[1-14C]lactate or a mixture of51Cr-labeled erythrocytes, [14C]sucrose, andl-[2-3H]lactate was injected into the portal vein, and samples were obtained from the hepatic vein. Data were evaluated using a model comprising flow along sinusoids, exchange of lactate between plasma and erythrocytes and between plasma and hepatocytes, and, in the case ofl-[1-14C]lactate, metabolism to H[14C][Formula: see text]within hepatocytes. The coefficient for lactate efflux from erythrocytes was 0.62 ± 0.24 s−1, and those for influx into and efflux from hepatocytes were 0.44 ± 0.13 and 0.14 ± 0.07 s−1, respectively. The influx permeability-surface area product of the hepatocyte membrane for lactate ( P in S, in ml ⋅ s−1 ⋅ g−1) varied with total flow rate ( F, in ml s−1 ⋅ g−1) according to P in S = (3.1 ± 0.5) F+ (0.021 ± 0.014). Lactate in plasma, erythrocytes, and hepatocytes was close to equilibrium, whereas lactate metabolism was rate limiting.

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