Tracheal epithelial damage alters tracer fluxes and effects of tracheal osmolaity in sheep in vivo

1995 ◽  
Vol 78 (5) ◽  
pp. 1921-1930 ◽  
Author(s):  
U. M. Wells ◽  
A. J. Woods ◽  
Z. Hanafi ◽  
J. G. Widdicombe
Keyword(s):  
Blood Flow ◽  
Permeability Coefficient ◽  
Water Movement ◽  
Venous Blood ◽  
Water Flux ◽  
Tracheal Lumen ◽  
Epithelial Damage ◽  
Tracheal Epithelial ◽  
Triton X

Tracheal osmolaity affects blood flow and the flux of a tracer, technetium-99m-labeled diethylenetriamine pentaacetic acid (99mTc-DTPA), from tracheal lumen to venous blood in anesthetized sheep. Hyperosmolar liquids increase blood flow and slightly decrease 99mTc-DTPA flux, whereas hyposmolar liquids have no effect on blood flow and greatly increase 99mTc-DTPA flux. We have now investigated whether epithelial damage induced by exposure of the tracheal lumen to a detergent (0.2% Triton X-100) alters these effects. A tracheal artery was perfused, and tracheal venous blood was collected. The initial tracheal volume was 12.8 +/- 0.7 ml. Triton X-100 greatly increased the permeability coefficient for 99mTc-DTPA from -2.1 x 10(-7) to -240 x 10(-7) cm/s. Hyperosmolar Krebs-Henseleit solution (KH; 739 +/- 6 mosmol/kg) increased arterial (+14.3%) and venous (+21.5%) flows and decreased 99mTc-DTPA output by 51.7%. Water flux into the lumen (+0.3 +/- 0.1 ml) was not significant, and the osmolality decreased by 99 +/- 9 mosmol/kg. Hyposmolar KH (124 +/- 2 mosmol/kg) had no effect on arterial and venous flows (-1.3% for both), and the increase in 99mTc-DTPA output (+8.3%) was small and not significant. The volume decreased by 0.4 +/- 0.1 ml, and the osmolaity increased by 36 +/- 4 mosmol/kg. Thus epithelial damage greatly increases the baseline permeability of the tracheal wall to 99mTc-DTPA. It does not alter the qualitative effects of hypersomolar KH on blood flow and 99mTc-DTPA output but does reduce the effect of hyposmolar KH on 99mTc-DTPA output. The latter effect may be a consequence of the reduced net water movement in response to non-isosmolar solutions after epithelial damage.

scholarly journals H2O2increases sheep tracheal blood flow, permeability, and vascular response to luminal capsaicin

1997 ◽  
Vol 82 (2) ◽  
pp. 621-631 ◽  
Author(s):  
U. M. Wells ◽  
S. Duneclift ◽  
J. G. Widdicombe
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Tracer Uptake ◽  
T Test ◽  
Airway Epithelial ◽  
Vascular Response ◽  
Epithelial Damage ◽  
Afferent Nerve Endings

Wells, U. M., S. Duneclift, and J. G. Widdicombe.H2O2increases sheep tracheal blood flow, permeability, and vascular response to luminal capsaicin. J. Appl. Physiol. 82(2): 621–631, 1997.—Exogenous hydrogen peroxide (H2O2) causes airway epithelial damage in vitro. We have studied the effects of luminal H2O2in the sheep trachea in vivo on tracheal permeability to low-molecular-weight hydrophilic (technetium-99m-labeled diethylenetriamine pentaacetic acid;99mTc-DTPA) and lipophilic ([14C]antipyrine; [14C]AP) tracers and on the tracheal vascular response to luminal capsaicin, which stimulates afferent nerve endings. A tracheal artery was perfused, and tracheal venous blood was collected. H2O2exposure (10 mM) reduced tracheal potential difference (−42.0 ± 6.4 mV) to zero. It increased arterial and venous flows (56.7 ± 6.1 and 57.3 ± 10.0%, respectively; n = 5, P < 0.01, paired t-test) but not tracheal lymph flow (unstimulated flow 5.0 ± 1.2 μl ⋅ min−1⋅ cm−1, n = 4). During H2O2exposure, permeability to99mTc-DTPA increased from −2.6 to −89.7 × 10−7cm/s ( n = 5, P < 0.05), whereas permeability to [14C]AP (−3,312.6 × 10−7cm/s, n = 4) was not altered significantly (−2,565 × 10−7cm/s). Luminal capsaicin (10 μM) increased tracheal blood flow (10.1 ± 4.1%, n = 5) and decreased venous99mTc-DTPA concentration (−19.7 ± 4.0, P < 0.01), and these effects were significantly greater after epithelial damage (28.1 ± 6.0 and −45.7 ± 4.3%, respectively, P < 0.05, unpaired t-test). Thus H2O2increases the penetration of a hydrophilic tracer into tracheal blood and lymph but has less effect on a lipophilic tracer. It also enhances the effects of luminal capsaicin on blood flow and tracer uptake.

Osmolality alters tracheal blood flow and tracer uptake in anesthetized sheep

1994 ◽  
Vol 77 (5) ◽  
pp. 2400-2407 ◽  
Author(s):  
U. M. Wells ◽  
Z. Hanafi ◽  
J. G. Widdicombe
Keyword(s):  
Blood Flow ◽  
Water Movement ◽  
Venous Blood ◽  
Tracer Uptake ◽  
Solute Flux ◽  
Airway Surface Liquid ◽  
Tracheal Lumen ◽  
Airway Wall ◽  
Paracellular Pathways ◽  
Surface Liquid

Changes in the osmolality of airway surface liquid cause bronchoconstriction, mucus secretion, and ion transport, but little is known about the effects on the permeability of the trachea to drugs applied to the tracheal lumen. Using the anesthetized sheep, we have investigated the effects of hyperosmolar (725 +/- 11 mosmol/kg) and hyposmolar (128 +/- 5 mosmol/kg) Krebs-Henseleit (KH) solution in the tracheal lumen (mean volume 13.6 ml) on the uptake of technetium-99m-labeled diethylenetriamine pentaacetic acid (99mTc-DTPA), a low-molecular-mass hydrophilic tracer that is thought to cross the epithelium via paracellular pathways, and on blood flow. All changes in osmolality were made by altering the NaCl content. We perfused a tracheal artery and collected tracheal venous blood. Hyperosmolar KH increased water movement into the lumen (+2.0 ml) and solute flux out of the lumen. It increased arterial (+24.5%) and venous (+20.6%) flows and decreased 99mTc-DTPA concentration (-26.3%) and output (-12.0%) in venous blood. Hyposmolar KH caused water movement out of the lumen (-0.9 ml) and solute flux into the lumen. It had no effect on arterial (+0.6%) and venous (+5.5%) flows and greatly increased the concentration (+345%) and output (+375%) of 99mTc-DTPA in venous blood. The baseline permeability coefficient for 99mTc-DTPA (-9.1 x 10(-7) cm/s) was not affected by hyperosmolar KH (-8.7 x 10(-7) cm/s) but was increased by hyposmolar KH (-21.4 x 10(-7) cm/s). These results confirm that hyperosmolar liquid in the lumen increases blood flow and indicate that tracer uptake is affected by the bulk flow of water across the airway wall.

scholarly journals Testicular microvascular flow is altered in Klinefelter syndrome and predicts circulating testosterone

2021 ◽  
Author(s):  
Francesco Carlomagno ◽  
Carlotta Pozza ◽  
Marta Tenuta ◽  
Riccardo Pofi ◽  
Luigi Tarani ◽  
...  
Keyword(s):  
Blood Flow ◽  
Klinefelter Syndrome ◽  
Mean Transit Time ◽  
Venous Blood ◽  
Experimental Studies ◽  
Principal Component ◽  
Endocrine Function ◽  
Venous Blood Flow ◽  
Testicular Blood Flow

ABSTRACTContextExperimental studies on Klinefelter syndrome (KS) reported increased intratesticular testosterone (T) levels coexisting with reduced circulating levels. Abnormalities in testicular microcirculation have been claimed; however, no studies investigated in vivo testicular blood flow dynamics in humans with KS.ObjectiveTo analyze the testicular microcirculation in KS by contrast-enhanced ultrasonography (CEUS) and correlate vascular parameters with endocrine function.Design and SettingProspective study. University Settings.Patients51 testicular scans, 17 testes from 10 T-naïve subjects with KS and 34 testes from age-matched eugonadal men (CNT) who underwent CEUS for incidental nonpalpable testicular lesions.Main OutcomesCEUS kinetic parameters.ResultsCEUS revealed slower testicular perfusion kinetics in subjects with KS than in age-matched CNT. Specifically, the wash-in time (Tin, p = 0.008), mean transit time (MTT, p = 0.008), time to peak (TTP, p < 0.001), and washout time (Tout 50%, p = 0.008) were all prolonged. Faster testicular blood flow was associated with higher total T levels. Principal component analysis and multiple linear regression analyses confirmed the findings, and supported a role for reduced venous blood flow as independent predictor of total T levels.ConclusionsTesticular venous blood flow is altered in KS and independently predicts T peripheral release.

Hemodynamics and metabolism of the in vivo vascularly isolated canine pancreas.

1979 ◽  
Vol 236 (6) ◽  
pp. E626
Author(s):  
R J Alteveer ◽  
M J Jaffe ◽  
J Van Dam
Keyword(s):  
Blood Flow ◽  
Glucose Uptake ◽  
Venous Blood ◽  
Fatty Acid Uptake ◽  
Acid Uptake ◽  
Anesthetized Dogs ◽  
Metabolic Variables ◽  
The Stability ◽  
First Time

Surgical procedures are detailed that have yielded for the first time an in vivo vascularly isolated, autoperfused preparation of the entire pancreas in anesthetized dogs. Previous studies had isolated only part of the pancreas or had resorted to blood-flow techniques not requiring pooled pancreatic venous blood, necessary for metabolic studies of the organ. Pancreatic blood flow (48 ml/min), O2 uptake (180 mumol/min), glucose uptake (51.0 mumol/min), lactate output (6.6 mumol/min), net free fatty acid uptake (2.23 mumol/min), all per 100 g tissue, and various other measured and calculated hemodynamic and metabolic variables were determined on the preparation during control conditions. The stability of the preparation was verified by serial determinations of these parameters and of blood alpha-amylase and beta-glucuronidase levels from 1 to 2.5 h postsurgery. Metabolic rate and glucose uptake were both found to be much higher than in intestinal tissues and approached values characteristic of liver tissue.

Blood flow in the ovary and adjacent structures of the non-pregnant sheep

1983 ◽  
Vol 103 (2) ◽  
pp. 259-265 ◽  
Author(s):  
P. O. Janson ◽  
D. Williams ◽  
O. M. Petrucco ◽  
F. Amato ◽  
R. F. Seamark ◽  
...  
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Vascular Pedicle ◽  
Venous Flow ◽  
Adjacent Structures ◽  
Pregnant Sheep ◽  
Rapid Changes ◽  
Capillary Bed

Abstract. Blood flow to the ovary, vascular pedicle and oviduct was measured in anaesthetized non-cycling and cycling ewes by timed collection of ovarian venous blood. The degree of arterio-venous shunting across the ovary and pedicle was estimated both in vivo and in vitro by perfusing the tissues with 15 ± 5 μm radioactive microspheres. The mean ovarian blood flow in non-cycling animals was 1.9 ml/min, which was 51% of blood flow in the ovarian vein. In cycling animals ovarian blood flow at midcycle was 2.9 ml/min (66% of ovarian venous flow) in non-luteal ovaries and 4.3 ml/min (79% of venous flow) in luteal ovaries. The degree of arterio-venous shunting was low in all stages of the cycle (1.0–2.6% across ovary + pedicle). The degree of shunting was also found to be very small in vitro (0.007–1.38%) in both non-luteal and luteal ovaries. A considerable number of microspheres was entrapped in the vascular pedicle of the ovary indicating the presence of an extensive capillary bed. There was an inverse relationship between blood flow in the ovary and flow in the vascular pedicle. Alterations in distribution of blood flow between the ovary and adjacent structures supplied by the ovarian artery may be of functional significance in allowing rapid changes in ovarian blood flow. The results of the present study indicate that changes in ovarian blood flow during the oestrous cycle are not caused by an action on arteriovenous shunt vessels.

scholarly journals Testicular microvascular flow is altered in Klinefelter syndrome and predicts circulating testosterone

2021 ◽  
Author(s):  
Francesco Carlomagno ◽  
Carlotta Pozza ◽  
Marta Tenuta ◽  
Riccardo Pofi ◽  
Luigi Tarani ◽  
...  
Keyword(s):  
Blood Flow ◽  
Klinefelter Syndrome ◽  
Mean Transit Time ◽  
Venous Blood ◽  
Experimental Studies ◽  
Principal Component ◽  
Endocrine Function ◽  
Venous Blood Flow ◽  
Testicular Blood Flow

Abstract Context Experimental studies on Klinefelter syndrome (KS) reported increased intratesticular testosterone (T) levels coexisting with reduced circulating levels. Abnormalities in testicular microcirculation have been claimed; however, no studies investigated in vivo testicular blood flow dynamics in humans with KS. Objective To analyze the testicular microcirculation in KS by contrast-enhanced ultrasonography (CEUS) and correlate vascular parameters with endocrine function. Design and Setting Prospective study. University Setting. Patients 68 testicular scans, 34 testes from 19 T-naïve subjects with KS and 34 testes from age-matched eugonadal men (CNT) who underwent CEUS for incidental nonpalpable testicular lesions. Main Outcomes. CEUS kinetic parameters. Results CEUS revealed slower testicular perfusion kinetics in subjects with KS than in age-matched CNT. Specifically, the wash-in time (Tin, p = 0.018), mean transit time (MTT, p = 0.035), time to peak (TTP, p &lt; 0.001), and washout time (Tout 50%, p = 0.004) were all prolonged. Faster testicular blood flow was associated with higher total T levels. Principal component analysis and multiple linear regression analyses confirmed the findings, and supported a role for reduced venous blood flow as independent predictor of total T levels. Conclusions Testicular venous blood flow is altered in KS and independently predicts T peripheral release.

Evidence that aquaporin-1 mediates NaCl-induced water flux across descending vasa recta

1997 ◽  
Vol 272 (5) ◽  
pp. F587-F596 ◽  
Author(s):  
T. L. Pallone ◽  
B. K. Kishore ◽  
S. Nielsen ◽  
P. Agre ◽  
M. A. Knepper
Keyword(s):  
Water Permeability ◽  
Water Movement ◽  
Water Flux ◽  
Water Channel ◽  
Enzyme Linked Immunosorbent Assay ◽  
Aquaporin 1 ◽  
Vasa Recta ◽  
Water Efflux

Outer medullary descending vasa recta (OMDVR) were perfused in vitro, and volume efflux was measured by driving water movement with transmural gradients of NaCl or albumin. Consistent with mediation by water channels, p-chloromercuribenzenesulfonic acid (pCMBS) markedly inhibited volume flux induced by NaCl. Dithiothreitol reversed the inhibition, pCMBS did not significantly alter water flux induced by albumin. Osmotic water permeability (Pf) of the pCMBS-sensitive pathway of glutaraldehyde-fixed and nonfixed OMDVR was 1,102 +/- 449 and 1,257 +/- 718 microns/s (means +/- SD), respectively. pCMBS reduced Pf to near zero, whereas diffusional water permeability in the same vessels was only slightly inhibited. Immunoreactive aquaporin-1 (AQP1) measured by enzyme-linked immunosorbent assay in collagenase-treated and untreated OMDVR was 5.2 +/- 1.0 and 4.2 +/- 0.4 fmol/mm, respectively, values that account well for the experimental Pf. We conclude that OMDVR water flux driven by NaCl gradients is most likely mediated by the AQP1 water channel and that NaCl and urea gradients drive water efflux in vivo by this route.

The mechanism of water absorption by roots II. The role of hydrostatic pressure gradients across the cortex

1957 ◽  
Vol 147 (928) ◽  
pp. 381-391 ◽  
Keyword(s):  
Mass Flow ◽  
Pressure Difference ◽  
Permeability Coefficient ◽  
Water Movement ◽  
External Medium ◽  
Water Flux ◽  
Applied Pressure ◽  
Pressure Gradients ◽  
Xylem Elements ◽  
Flow Pathway

Using methods described in Part I differences of pressure were applied between the external medium and the xylem elements of tomato root systems. The pressure permeability coefficient k p (the water flux per unit pressure difference), and the osmotic permeability coefficient k 0 (the water flux per unit difference of osmotic potential between the external medium and the xylem elements) were compared under similar conditions of applied pressure. Also k 0 was measured in the presence and absence of pressure gradients. The most striking effect of applying a pressure gradient was an increase in k 0 , 2 atm commonly causing a five-fold increase. Thus diffusion of water across the cortex was greatly facilitated by a pressure gradient. In addition it was found that under similar pressure conditions k p was consistently greater than k 0 , k p / k 0 being about 1·3 with an applied pressure difference of 2 atm. This indicated a mass flow of about a quarter of the total flux under these conditions. This dual nature of the water movement was confirmed by the action of cyanide and anaerobic conditions which caused a greater reduction in k 0 than k p showing that the diffusional pathway was more sensitive to decreased metabolism than the mass flow pathway. The effect of pressure gradients on diffusional water movement and the possible location of the mass flow pathway are briefly discussed as are their implications with reference to transpirational tensions and the uptake of solutes from the soil.

scholarly journals CGRP outflow into jugular blood and cerebrospinal fluid and permeance for CGRP of rat dura mater

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Miriam Risch ◽  
Birgit Vogler ◽  
Mária Dux ◽  
Karl Messlinger
Keyword(s):  
Blood Flow ◽  
Cerebrospinal Fluid ◽  
Dura Mater ◽  
Ex Vivo ◽  
Venous Blood ◽  
Extracellular Fluid ◽  
Fold Increase ◽  
Primary Headaches ◽  
Subarachnoidal Space

Abstract Background Calcitonin gene-related peptide (CGRP) is released from activated meningeal afferent fibres in the cranial dura mater, which likely accompanies severe headache attacks. Increased CGRP levels have been observed in different extracellular fluid compartments during primary headaches such as migraine but it is not entirely clear how CGRP is drained from the meninges. Methods We have used an in vivo preparation of the rat to examine after which time and at which concentration CGRP applied onto the exposed parietal dura mater appears in the jugular venous blood and the cerebrospinal fluid (CSF) collected from the cisterna magna. Recordings of meningeal (dural) and cortical (pial) blood flow were used to monitor the vasodilatory effect of CGRP. In a new ex vivo preparation we examined how much of a defined CGRP concentration applied to the arachnoidal side penetrates the dura. CGRP concentrations were determined with an approved enzyme immunoassay. Results CGRP levels in the jugular plasma in vivo were slightly elevated compared to baseline values 5-20 min after dural application of CGRP (10 μM), in the CSF a significant three-fold increase was seen after 35 min. Meningeal but not cortical blood flow showed significant increases. The spontaneous CGRP release from the dura mater ex vivo was above the applied low concentration of 1 pM. CGRP at 1 nM did only partly penetrate the dura. Conclusions We conclude that only a small fraction of CGRP applied onto the dura mater reaches the jugular blood and, in a delayed manner, also the CSF. The dura mater may constitute a barrier for CGRP and limits diffusion into the CSF of the subarachnoidal space, where the CGRP concentration is too low to cause vasodilatation.

scholarly journals Arterio-Venous Branchial Blood Flow in the Atlantic Cod Gadus Morhua

1992 ◽  
Vol 165 (1) ◽  
pp. 73-84 ◽  
Author(s):  
LENA SUNDIN ◽  
STEFAN NILSSON
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Atlantic Cod ◽  
Vascular System ◽  
Venous Blood ◽  
Venous Blood Flow ◽  
Venous Flow ◽  
Flow Measurements ◽  
Vasomotor Function

We have estimated the branchial venous blood flow in the Atlantic cod by direct single-crystal Doppler blood flow measurements in vivo. In the undisturbed animal, this flow amounts to 1.7 ml min−1 kg−1, which corresponds to about 8 % of the cardiac output. Studies of both an isolated perfused gill apparatus in situ and simultaneous measurements of cardiac output and branchial venous flow in vivo were made to assess the effects of some putative vasoregulatory substances. Adrenaline dilates the arterio-arterial pathway and constricts the arterio-venous pathway, thus decreasing branchial venous drainage. 5-Hydroxytryptamine (5-HT), in contrast, produced marked vasoconstriction in the arterio-arterial pathway of the branchial vasculature, increasing the branchial venous blood flow. Cholecystokinin-8 (CCK-8) and caerulein produced similar cardiovascular effects, with marked constriction of both arterio-arterial and arterio-venous pathways. The study demonstrates the ability of the vascular system of the gills to regulate the distribution of branchial blood flow, and summarizes the vasomotor effects of some substances with possible vasomotor function in the cod gills.

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