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.

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.

scholarly journals Effect of spontaneous breathing on umbilical venous blood flow and placental transfusion during delayed cord clamping in preterm lambs

2019 ◽  
Vol 105 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Emma Brouwer ◽  
Arjan B te Pas ◽  
Graeme R Polglase ◽  
Erin V McGillick ◽  
Stefan Böhringer ◽  
...  
Keyword(s):  
Blood Flow ◽  
Body Weight ◽  
Spontaneous Breathing ◽  
Venous Blood ◽  
Vena Cava ◽  
Venous Blood Flow ◽  
Delayed Cord Clamping ◽  
Venous Flow ◽  
Cord Clamping ◽  
Pregnant Sheep

IntroductionDuring delayed umbilical cord clamping, the factors underpinning placental transfusion remain unknown. We hypothesised that reductions in thoracic pressure during inspiration would enhance placental transfusion in spontaneously breathing preterm lambs.ObjectiveInvestigate the effect of spontaneous breathing on umbilical venous flow and body weight in preterm lambs.MethodsPregnant sheep were instrumented at 132–133 days gestational age to measure fetal common umbilical venous, pulmonary and cerebral blood flows as well as arterial and intrapleural (IP) pressures. At delivery, doxapram and caffeine were administered to promote breathing. Lamb body weights were measured continuously and breathing was assessed by IP pressure changes.ResultsIn 6 lambs, 491 out of 1117 breaths were analysed for change in body weight. Weight increased in 46.6% and decreased in 47.5% of breaths. An overall mean increase of 0.02±2.5 g per breath was calculated, and no net placental transfusion was observed prior to cord clamping (median difference in body weight 52.3 [−54.9–166.1] g, p=0.418). Umbilical venous (UV) flow transiently decreased with each inspiration, and in some cases ceased, before UV flow normalised during expiration. The reduction in UV flow was positively correlated with the standardised reduction in (IP) pressure, increasing by 109 mL/min for every SD reduction in IP pressure. Thus, the reduction in UV flow was closely related to inspiratory depth.ConclusionsSpontaneous breathing had no net effect on body weight in preterm lambs at birth. UV blood flow decreased as inspiratory effort increased, possibly due to constriction of the inferior vena cava caused by diaphragmatic contraction, as previously observed in human fetuses.

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.

Neuromuscular electrical stimulation for thromboprophylaxis: A systematic review

2015 ◽  
Vol 30 (9) ◽  
pp. 589-602 ◽  
Author(s):  
S Hajibandeh ◽  
S Hajibandeh ◽  
GA Antoniou ◽  
JRH Scurr ◽  
F Torella
Keyword(s):  
Systematic Review ◽  
Blood Flow ◽  
Electrical Stimulation ◽  
Venous Thromboembolism ◽  
Venous Blood ◽  
Neuromuscular Electrical Stimulation ◽  
Current Evidence ◽  
Venous Blood Flow ◽  
Flow Measurements ◽  
Blood Flow Measurements

Objective To evaluate the effect of neuromuscular electrical stimulation on lower limb venous blood flow and its role in thromboprophylaxis. Method Systematic review of randomised and non-randomised studies evaluating neuromuscular electrical stimulation, and reporting one or more of the following outcomes: incidence of venous thromboembolism, venous blood flow and discomfort profile. Results Twenty-one articles were identified. Review of these articles showed that neuromuscular electrical stimulation increases venous blood flow and is generally associated with an acceptable tolerability, potentially leading to good patient compliance. Ten comparative studies reported DVT incidence, ranging from 2% to 50% with neuromuscular electrical stimulation and 6% to 47.1% in controls. There were significant differences, among included studies, in terms of patient population, neuromuscular electrical stimulation delivery, diagnosis of venous thromboembolism and blood flow measurements. Conclusion Neuromuscular electrical stimulation increases venous blood flow and is well tolerated, but current evidence does not support a role for neuromuscular electrical stimulation in thromboprophylaxis. Randomised controlled trials are required to investigate the clinical utility of neuromuscular electrical stimulation in this setting.

Circulatory Effects of Hypoxia, Acute Normovolemic Hemodilution, and Their Combination in Anesthetized Pigs

1996 ◽  
Vol 84 (6) ◽  
pp. 1443-1454 ◽  
Author(s):  
Henning Schou ◽  
Valeria Perez de Sa ◽  
Maria Sigurdardottir ◽  
Roger Roscher ◽  
Christer Jonmarker ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Oxygen Saturation ◽  
Venous Blood ◽  
Mixed Venous Oxygen Saturation ◽  
Venous Blood Flow ◽  
Arterial Lactate ◽  
Venous Oxygen Saturation ◽  
Systemic Oxygen ◽  
Mixed Venous

Background Because hemodilution decreases the oxygen-carrying capacity of blood, it was hypothesized that severe hemodilution would decrease the tolerance to alveolar hypoxia. Methods Hemodynamics, oxygen transport, and blood lactate concentrations were compared in ten pigs with normal hematocrit (33 +/- 4%), and ten hemodiluted pigs (hematocrit 11 +/- 1%; mean +/- SD) anesthetized with ketamine-fentanyl-pancuronium during stepwise decreases in inspired oxygen fraction (FIO2; 1.0, 0.35, 0.21, 0.15, 0.10, 0.05). Results Median systemic oxygen delivery (DO2SY) became critical (the DO2SY value when arterial lactate exceeded 2.0 mmol.l-1) at 10.4 ml.kg-1.min-1 (range 6.9-16.1) in hemodiluted animals and at 11.8 ml.kg-1.min-1 (5.9-32.2) in animals with normal hematocrits (NS). The relationship between mixed venous oxygen saturation and arterial lactate values was less consistent and median critical mixed venous oxygen saturation was higher (P &lt; 0.05) in the hemodiluted group (35%, range 21-64), than in animals with normal hematocrits (21%, 7-68%). In animals with normal hematocrit, decreasing FIO2 from 1.0 to 0.10 resulted in a decrease in DO2SY from 26.3 +/- 9.1 to 9.3 +/- 3.9 ml.kg-1.min-1 (P &lt; 0.01). Cardiac output did not change, systemic oxygen extraction ratio increased from 0.23 +/- 0.08 to 0.68 +/- 0.13 (P &lt; 0.01), and arterial lactate from 0.9 +/- 0.2 to 3.4 +/- 3.0 mmol.l-1 (P &lt; 0.05). Cardiac venous blood flow, as measured by retrograde thermodilution, increased from 5.7 +/- 2.9 to 12.6 +/- 5.7 ml.kg-1.min-1 (P &lt; 0.01). When FIO2 was reduced to 0.05, three animals became hypotensive and died. In the second group, hemodilution increased cardiac output and systemic oxygen extraction ratio (P &lt; 0.01). Cardiac venous blood flow increased from 4.1 +/- 1.7 to 9.8 +/- 5.1 ml.kg-1.min-1 (P &lt; 0.01), and cardiac venous oxygen saturation from 22 +/- 5 to 41 +/- 10% (P &lt; 0.01). During the subsequent hypoxia, cardiac output and DO2SY were maintained until FIO2 = 0.15 (DO2SY = 10.1 +/- 3.3 ml.kg-1.min-1). Cardiac venous blood flow was then 18.5 +/- 10.7 ml.kg-1.min-1 (P &lt; 0.01), but in spite of this, myocardial lactate production occurred. At FIO2 = 0.10 (DO2SY = 7.7 +/- 3.0 ml.kg-1.min-1), arterial lactate concentration increased to 8.5 +/- 2.3 mmol.l-1 (P &lt; 0.01), and most animals became hypotensive. All hemodiluted animals died when FIO2 was decreased to 0.05 (P &lt; 0.01 when compared to animals with normal hematocrit). Conclusions Systemic and myocardial lactate production occurred at similar systemic oxygen delivery rates in hemodiluted and nonhemodiluted animals. Mixed venous oxygen saturation may be a less reliable indicator of inadequate oxygen delivery during hemodilution.

Compensatory mechanisms in response to an elevated hepatic oxygen consumption in chronically ethanol-fed rats

1985 ◽  
Vol 248 (5) ◽  
pp. G507-G511 ◽  
Author(s):  
J. E. Bredfeldt ◽  
E. M. Riley ◽  
R. J. Groszmann
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Hepatic Artery ◽  
Oxygen Delivery ◽  
Venous Blood ◽  
Venous Blood Flow ◽  
Compensatory Mechanisms ◽  
Hepatic Oxygen Consumption ◽  
Portal Venous Blood

During conditions that elevate hepatic oxygen consumption (VLO2), oxygen delivery, or oxygen extraction may also increase, acting as compensatory mechanisms. VLO2 was quantitated by an in vivo method in chronically ethanol-fed rats to establish whether VLO2 was increased and what compensatory mechanisms might ensue. VLO2 was increased 45% (0.32 +/- 0.02 ml O2 X min-1 X 100 g body wt-1; P less than 0.001) in rats chronically fed ethanol for 8 wk, while VLO2 (0.28 +/- 0.04; P = NS) was not increased in chronically ethanol-fed rats withdrawn from ethanol 20 h before study compared with control rats (0.22 +/- 0.01). Oxygen delivery was increased 31% (P less than 0.05) in ethanol-fed rats and adequately compensated for the increased VLO2. Hepatic artery blood flow did not increase in ethanol-fed rats, indicating a lack of hepatic artery vasodilation in response to the elevated VLO2. As a result, a greater percentage of oxygen delivery was supplied via portal venous blood flow that has a reduced oxygen content. These observations might suggest that ethanol-fed rats may have a decreased reserve for maintaining an adequate oxygen supply to the liver and may be at an increased liability for developing hepatic hypoxia if oxygen delivery and/or extraction were compromised.

scholarly journals OP19.11: Umbilical venous blood flow measurements: comparison between free and intra-abdominal portion

2009 ◽  
Vol 34 (S1) ◽  
pp. 124-124
Author(s):  
J. Carrillo ◽  
M. Yamamoto ◽  
D. Pedraza ◽  
H. Munoz ◽  
P. Valentini ◽  
...  
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Venous Blood Flow ◽  
Flow Measurements ◽  
Blood Flow Measurements ◽  
Abdominal Portion
Sign in / Sign up

Export Citation Format

Share Document