Effects of ligation and embolization on Kf and multiple tracer measurements in dog lungs

1990 ◽  
Vol 69 (4) ◽  
pp. 1460-1466 ◽  
Author(s):  
J. D. Bradley ◽  
R. E. Parker ◽  
T. R. Harris ◽  
K. A. Overholser
Keyword(s):  
Surface Area ◽  
Glass Bead ◽  
Glass Beads ◽  
Lung Weight ◽  
Capillary Filtration ◽  
Permeability Surface ◽  
Capillary Filtration Coefficient ◽  
Before And After ◽  
Filtration Area ◽  
Area Product

In isolated blood-perfused dog lungs, the capillary filtration coefficient (Kf) and the permeability-surface area product of urea (PS) were measured to determine their responses to two different methods of altering filtration area: lobe ligation (LL, n = 5) and glass bead embolization (GBE, n = 4) during constant perfusion rates (700 +/- 45 ml/min). When two of three lobes were ligated, Kf decreased (1.36 +/- 0.13 to 0.58 +/- 0.23 g.min-1.cmH2O-1; P less than 0.05), but PS did not change (2.02 +/- 0.4 to 1.71 +/- 0.3 ml/s). Kf per gram of perfused blood-free dry lung weight was unchanged by LL (0.051 +/- 0.17 to 0.052 +/- 0.18 g.min-1.cmH2O-1), indicating that surface area per gram measured by Kf remained the same. However, PS per gram dry lung doubled (0.07 +/- 0.016 to 0.146 +/- 0.06 ml/s; P less than 0.05) after LL, suggesting that recruitment occurred in the remaining lobe. When three lobes were embolized with 200-microns glass beads (0.48 +/- 0.01 g beads/kg body wt), PS decreased (2.1 +/- 0.22 to 0.94 +/- 0.09 ml/s; P less than 0.05), but Kf was not altered (1.01 +/- 0.17 to 1.04 +/- 0.18 g.min-1.cmH2O-1). The constancy of Kf after GBE implies that the vascular pressure increase during the Kf measurement was transmitted to both blocked and flowing vessels and thereby measured the same filtration area before and after GBE. PS decreased significantly after GBE because of a loss of perfused surface area by the beads blocking flow in small arterial vessels.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of common vasodilators on lung microvascular permeability

1993 ◽  
Vol 75 (5) ◽  
pp. 2326-2331 ◽  
Author(s):  
J. A. Swanson ◽  
D. F. Kern
Keyword(s):  
Reflection Coefficient ◽  
Surface Area ◽  
Capillary Filtration ◽  
Vascular Surface ◽  
Isolated Perfused Lung ◽  
Permeability Surface ◽  
Capillary Filtration Coefficient ◽  
Perfused Lung ◽  
Area Product ◽  
Lung Surface Area

The effect of papaverine on the albumin permeability-surface area product (PS), reflection coefficient (sigma), and capillary filtration coefficient (Kf) was examined in isolated rabbit lungs. Because PS and Kf are functions of vascular surface area and permeability, we also compared papaverine with two other means of maximizing lung surface area: isoproterenol (1 x 10(-7) M) and a mild increase in vascular pressure. Only lungs perfused with 0.1 mg/ml papaverine were significantly different from control. PS increased from control (2.80 +/- 0.16 to 5.53 +/- 0.20 ml.min-1.g dry lung-1 x 10(-2), whereas sigma decreased from control (0.92 +/- 0.01 to 0.78 +/- 0.03). Kf after papaverine was significantly lower than baseline predrug Kf (5.60 +/- 0.78 to 4.56 +/- 0.53 ml.s-1.cmH2O-1.g dry lung-1 x 10(-3). However, this group's predrug Kf was higher than that of any other group. Our results indicate that papaverine increases albumin permeability and decreases endothelial selectivity. The isolated perfused lung appears fully recruited, because Kf and PS did not increase with isoproterenol or increased vascular pressure. Papaverine should be used with caution in the Ringer-perfused lung.

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.

Forelimb blood flow distribution during hypothalamic dilator response

1976 ◽  
Vol 230 (6) ◽  
pp. 1561-1568 ◽  
Author(s):  
RP Menninger ◽  
CH Baker
Keyword(s):  
Blood Flow ◽  
Surface Area ◽  
Flow Distribution ◽  
Hypothalamic Stimulation ◽  
Blood Flow Distribution ◽  
Vascular Volume ◽  
Capillary Filtration ◽  
Flow Channels ◽  
Permeability Surface ◽  
Area Product

An attempt is made to determine whether hypothalamically induced forelimb vascular dilation in the dog affects primarily exchange beds or shunt circuits. Slug injections of [131I] albumin and 86RbCl were used to measure the active vascular volume of the forelimbs and permeability surface area product (PS), respectively. Changes in total vascular volume (TVV), filtration, and capillary filtration coefficient (CFD) were measured by plethysmography. During stimulation, forelimb blood flow increased 25% and TVV increased an average 1.5 ml. There was no plethysmographic evidence of outward capillary filtration. Active vascular volume decreased 11%. PS decreased 11%, and CFC decreased 20%. These results point to a redistribution of blood flow from exchange circuits to faster flow channels. During constant-inflow perfusion, there was evidence from CFC and PS measurements that the capillary surface area was increased while active vascular volume decreased. The results observed with hypothalamic stimulation are different from those obtained with pharmacologic dilators and denervation. It is suggested that the former method has a more selective effect in lowering resistance in the faster shuntlike vessels.

Isoflurane, but Not Sevoflurane, Increases Transendothelial Albumin Permeability in the Isolated Rat Lung

2006 ◽  
Vol 104 (4) ◽  
pp. 777-785 ◽  
Author(s):  
Guochang Hu ◽  
David E. Schwartz ◽  
Ayesha N. Shajahan ◽  
David J. Visintine ◽  
M Ramez Salem ◽  
...  
Keyword(s):  
Surface Area ◽  
Rat Lung ◽  
Caveolin 1 ◽  
Transendothelial Transport ◽  
Beta Cyclodextrin ◽  
Permeability Surface ◽  
Capillary Filtration Coefficient ◽  
Area Product ◽  
Isolated Lungs ◽  
Isolated Rat

Background Caveolae mediated transendothelial transport of albumin has recently been shown to be the primary mechanism regulating microvascular endothelial albumin permeability. The authors investigated the effects of isoflurane and sevoflurane on pulmonary endothelial albumin permeability and assessed the potential role of the caveolae scaffold protein, caveolin-1, in these effects. Methods Isolated rat lungs and cultured rat lung microvessel endothelial cells (RLMVECs) were exposed to 1.0 or 2.0 minimum alveolar concentration (MAC) isoflurane or sevoflurane for 30 min. I-albumin permeability-surface area product and capillary filtration coefficient were determined in the isolated lungs. In RLMVECs, uptake and transendothelial transport of I-albumin were measured in the absence and presence of pretreatment with 2 mm methyl-beta-cyclodextrin, a caveolae-disrupting agent. Uptake of fluorescent-labeled albumin, as well as phosphorylation of Src kinase and caveolin-1, was also determined. In Y14F-caveolin-1 mutant (nonphosphorylatable) expressing RLMVECs, uptake of I-albumin and phosphorylation of caveolin-1 were evaluated. Results In the isolated lungs, 2.0 MAC isoflurane increased I-albumin permeability-surface area product by 48% without affecting capillary filtration coefficient. In RLMVECs, isoflurane more than doubled the uptake of I-albumin and caused a 54% increase in the transendothelial transport of I-albumin. These effects were blocked by pretreatment with methyl-beta-cyclodextrin. The isoflurane-induced increase in uptake of I-albumin in wild-type RLMVECs was abolished in the Y14F-caveolin-1 mutant expressing cells. Isoflurane also caused a twofold increase in Src and caveolin-1 phosphorylation. Neither 1.0 MAC isoflurane nor 1.0 or 2.0 MAC sevoflurane affected any index of albumin transport or phosphorylation of caveolin-1. Conclusion Isoflurane, but not sevoflurane, increased lung transendothelial albumin permeability through enhancement of caveolae-mediated albumin uptake and transport in the isolated lung. This effect may involve an enhanced phosphorylation of caveolin-1.

Prevention of Nerve Edema and Increased Blood-Nerve Barrier Permeability-Surface Area Product in Galactosemic Rats by Aldose Reductase or Thromboxane Synthetase Inhibitors

Diabetes ◽  
1989 ◽  
Vol 38 (11) ◽  
pp. 1469-1477 ◽  
Author(s):  
K. C. Wadhwani ◽  
L. E. Caspers-Velu ◽  
V. A. Murphy ◽  
Q. R. Smith ◽  
P. F. Kador ◽  
...  
Keyword(s):  
Surface Area ◽  
Aldose Reductase ◽  
Barrier Permeability ◽  
Thromboxane Synthetase ◽  
Permeability Surface ◽  
Area Product

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.

Increased Hepatocyte Permeability Surface Area Product for86Rb With Increase in Blood Flow

1997 ◽  
Vol 80 (5) ◽  
pp. 645-654 ◽  
Author(s):  
Carl A. Goresky ◽  
André Simard ◽  
Andreas J. Schwab
Keyword(s):  
Blood Flow ◽  
Surface Area ◽  
Permeability Surface ◽  
Area Product

Use of [3H]methylglucose and [14C]iodoantipyrine to determine kinetic parameters of glucose transport in rat brain

1997 ◽  
Vol 272 (1) ◽  
pp. R163-R171
Author(s):  
K. Mori ◽  
M. Maeda
Keyword(s):  
Blood Flow ◽  
Surface Area ◽  
Glucose Transport ◽  
Tissue Samples ◽  
Arterial Blood ◽  
Permeability Surface ◽  
Time Courses ◽  
Area Product ◽  
Menten Kinetic ◽  
The Brain

Local maximal velocities of transport (Tmax) and the half-maximum transport constants (KT) for glucose transport across the blood-brain barrier have been determined in local regions of the brain in normal conscious rats. [14C]iodoantipyrine and [3H]methylglucose were infused together intravenously for 2 min in rats with plasma glucose concentrations maintained at different levels, and the time courses of the tracer levels in arterial blood were measured. Local 14C and 3H concentrations were then measured in tissue samples dissected from the frozen brains. By comparing the transport-limited uptake of [3H]methylglucose with the blood flow-limited uptake of [14C]iodoantipyrine, the value of m, a factor between 0 and 10 that accounts for diffusion and/or transport limitations, was derived, and from the equation, m = 1 - PS/F (where PS is capillary permeability-surface area product and F is cerebral blood flow), the permeability-capillary surface area for methylglucose was calculated (S. S. Kety. Pharmacol. Rev. 3: 1-41, 1951). Values for Tmax and KT for glucose were calculated by application of Michaelis-Menten kinetic relationships adapted for the competition for transport between glucose and methylglucose. Tmax was determined in three representative gray structures and one white structure of the brain: Tmax was 5.3 +/- 0.3 (SD) mumol.g-1.min-1 in the gray structures and 4.3 mumol.g-1.min-1 in the white structure. KT was 3.6 +/- 0.4 (SD) mM in the gray structures and 5.9 mM in the white structure. This approach allows the simultaneous determination of local values of Tmax and KT for glucose and the rates of blood flow in various regions of the brain in conscious animals.

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