scholarly journals Considerations for Numerical Modeling of the Pulmonary Circulation—A Review With a Focus on Pulmonary Hypertension

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
V. O. Kheyfets ◽  
W. O'Dell ◽  
T. Smith ◽  
J. J. Reilly ◽  
E. A. Finol
Keyword(s):  
Blood Flow ◽  
Pulmonary Hypertension ◽  
Pulmonary Blood Flow ◽  
Numerical Models ◽  
Academic Research ◽  
Basic Research ◽  
Wall Stress ◽  
Pulmonary Vasculature ◽  
Future Research ◽  
Wide Range

Both in academic research and in clinical settings, virtual simulation of the cardiovascular system can be used to rapidly assess complex multivariable interactions between blood vessels, blood flow, and the heart. Moreover, metrics that can only be predicted with computational simulations (e.g., mechanical wall stress, oscillatory shear index, etc.) can be used to assess disease progression, for presurgical planning, and for interventional outcomes. Because the pulmonary vasculature is susceptible to a wide range of pathologies that directly impact and are affected by the hemodynamics (e.g., pulmonary hypertension), the ability to develop numerical models of pulmonary blood flow can be invaluable to the clinical scientist. Pulmonary hypertension is a devastating disease that can directly benefit from computational hemodynamics when used for diagnosis and basic research. In the present work, we provide a clinical overview of pulmonary hypertension with a focus on the hemodynamics, current treatments, and their limitations. Even with a rich history in computational modeling of the human circulation, hemodynamics in the pulmonary vasculature remains largely unexplored. Thus, we review the tasks involved in developing a computational model of pulmonary blood flow, namely vasculature reconstruction, meshing, and boundary conditions. We also address how inconsistencies between models can result in drastically different flow solutions and suggest avenues for future research opportunities. In its current state, the interpretation of this modeling technology can be subjective in a research environment and impractical for clinical practice. Therefore, considerations must be taken into account to make modeling reliable and reproducible in a laboratory setting and amenable to the vascular clinic. Finally, we discuss relevant existing models and how they have been used to gain insight into cardiopulmonary physiology and pathology.

Noninvasive Investigation of Pulmonary Blood Flow in Children with Pulmonary Hypertension Using the TRV/RVOT VTI Ratio

2017 ◽  
Vol 65 (S 02) ◽  
pp. S111-S142
Author(s):  
M. Koestenberger ◽  
D. Baumgartner ◽  
G. Hansmann ◽  
S. Schweintzger ◽  
G. Grangl ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulmonary Hypertension ◽  
Pulmonary Blood Flow

scholarly journals A survey of methods for evaluating mini-publics

2021 ◽  
Author(s):  
Takeuchi Ayano
Keyword(s):  
Decision Making ◽  
Academic Research ◽  
Future Research ◽  
The Political ◽  
Decision Making Process ◽  
Sufficient Information ◽  
Practical Case ◽  
Political Decision ◽  
Wide Range ◽  
Political Decision Making

AbstractPublic participation has become increasingly necessary to connect a wide range of knowledge and various values to agenda setting, decision-making and policymaking. In this context, deliberative democratic concepts, especially “mini-publics,” are gaining attention. Generally, mini-publics are conducted with randomly selected lay citizens who provide sufficient information to deliberate on issues and form final recommendations. Evaluations are conducted by practitioner researchers and independent researchers, but the results are not standardized. In this study, a systematic review of existing research regarding practices and outcomes of mini-publics was conducted. To analyze 29 papers, the evaluation methodologies were divided into 4 categories of a matrix between the evaluator and evaluated data. The evaluated cases mainly focused on the following two points: (1) how to maintain deliberation quality, and (2) the feasibility of mini-publics. To create a new path to the political decision-making process through mini-publics, it must be demonstrated that mini-publics can contribute to the decision-making process and good-quality deliberations are of concern to policy-makers and experts. Mini-publics are feasible if they can contribute to the political decision-making process and practitioners can evaluate and understand the advantages of mini-publics for each case. For future research, it is important to combine practical case studies and academic research, because few studies have been evaluated by independent researchers.

scholarly journals Role of Insulin in Health and Disease: An Update

2021 ◽  
Vol 22 (12) ◽  
pp. 6403
Author(s):  
Md Saidur Rahman ◽  
Khandkar Shaharina Hossain ◽  
Sharnali Das ◽  
Sushmita Kundu ◽  
Elikanah Olusayo Adegoke ◽  
...  
Keyword(s):  
Insulin Signaling ◽  
Basic Research ◽  
Future Research ◽  
Protective Effects ◽  
Glucose Levels ◽  
Physiological Processes ◽  
Blood Glucose Levels ◽  
Wide Range ◽  
Health And Disease

Insulin is a polypeptide hormone mainly secreted by β cells in the islets of Langerhans of the pancreas. The hormone potentially coordinates with glucagon to modulate blood glucose levels; insulin acts via an anabolic pathway, while glucagon performs catabolic functions. Insulin regulates glucose levels in the bloodstream and induces glucose storage in the liver, muscles, and adipose tissue, resulting in overall weight gain. The modulation of a wide range of physiological processes by insulin makes its synthesis and levels critical in the onset and progression of several chronic diseases. Although clinical and basic research has made significant progress in understanding the role of insulin in several pathophysiological processes, many aspects of these functions have yet to be elucidated. This review provides an update on insulin secretion and regulation, and its physiological roles and functions in different organs and cells, and implications to overall health. We cast light on recent advances in insulin-signaling targeted therapies, the protective effects of insulin signaling activators against disease, and recommendations and directions for future research.

scholarly journals Personality trait differences across types of entrepreneurs: a systematic literature review

2021 ◽  
Author(s):  
Florentine U. Salmony ◽  
Dominik K. Kanbach
Keyword(s):  
Literature Review ◽  
Personality Traits ◽  
Systematic Literature Review ◽  
Empirical Studies ◽  
Academic Research ◽  
Future Research ◽  
Rural Farmers ◽  
Start Up ◽  
Wide Range ◽  
Research Integration

AbstractThe personality traits that define entrepreneurs have been of significant interest to academic research for several decades. However, previous studies have used vastly different definitions of the term “entrepreneur”, meaning their subjects have ranged from rural farmers to tech-industry start-up founders. Consequently, most research has investigated disparate sub-types of entrepreneurs, which may not allow for inferences to be made regarding the general entrepreneurial population. Despite this, studies have frequently extrapolated results from narrow sub-types to entrepreneurs in general. This variation in entrepreneur samples reduces the comparability of empirical studies and calls into question the reviews that pool results without systematic differentiation between sub-types. The present study offers a novel account by differentiating between the definitions of “entrepreneur” used in studies on entrepreneurs’ personality traits. We conduct a systematic literature review across 95 studies from 1985 to 2020. We uncover three main themes across the previous studies. First, previous research applied a wide range of definitions of the term “entrepreneur”. Second, we identify several inconsistent findings across studies, which may at least partially be due to the use of heterogeneous entrepreneur samples. Third, the few studies that distinguished between various types of entrepreneurs revealed differences between them. Our systematic differentiation between entrepreneur sub-types and our research integration offer a novel perspective that has, to date, been widely neglected in academic research. Future research should use clearly defined entrepreneurial samples and conduct more systematic investigations into the differences between entrepreneur sub-types.

Importance of adhesion molecules for children with congenital heart disease

2012 ◽  
Vol 23 (1) ◽  
pp. 35-40
Author(s):  
Ayşe Yıldırım ◽  
Aysu T. Karaağaç ◽  
Fusun Güzelmeriç ◽  
Nihat Çine ◽  
Naci C. Öner
Keyword(s):  
Blood Flow ◽  
Pulmonary Hypertension ◽  
Adhesion Molecules ◽  
Adhesion Molecule ◽  
Pulmonary Blood Flow ◽  
Congenital Heart ◽  
Heart Diseases ◽  
Cellular Adhesion ◽  
Mean Values ◽  
Cellular Adhesion Molecule

AbstractBackgroundThe aim of our study was to compare the blood levels of adhesion molecules in children with different heart diseases and pulmonary flow rates.MethodsIn this study, we evaluated the levels of soluble intercellular adhesion molecule-1 and soluble vascular cellular adhesion molecule-1 in blood samples of 65 children with different congenital heart diseases. The patients were divided into four groups according to their pulmonary blood flow. The first group had increased pulmonary blood flow with pulmonary hypertension and left-to-right shunt. The second group had increased pulmonary blood flow without pulmonary hypertension and left-to-right shunt. The third group had decreased pulmonary blood flow with cyanotic congenital heart disease and the fourth group had normal pulmonary blood flow with left ventricle outflow tract obstruction and aortic stenosis.ResultThe highest soluble intercellular and vascular cellular adhesion molecule-1 levels with the mean values of 420.2 nanograms per millilitre and 1382.1 nanograms per millilitre, respectively, were measured in the first group and the lowest levels with the mean values of 104.4 and 358.6 nanograms per millilitre, respectively, were measured in the fourth group. The highest pulmonary blood pressure levels were found in the first group.ConclusionEndothelial activity is influenced not only by left-to-right shunt with pulmonary hypertension, but also by decreased pulmonary blood flow in cyanotic heart diseases. Adhesion molecules are valuable markers of endothelial activity in congenital heart diseases, and they are influenced by pulmonary blood flow rate.

The pulmonary vasculature in a neonatal porcine model with increased pulmonary blood flow and pressure

2001 ◽  
Vol 11 (4) ◽  
pp. 420-430 ◽  
Author(s):  
Elisabeth V. Stenbøg ◽  
Daniel A. Steinbrüchel ◽  
Anne Bloch Thomsen ◽  
Ulrik Baandrup ◽  
Lene Heickendorff ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulmonary Artery ◽  
Vascular Disease ◽  
Pulmonary Blood Flow ◽  
Left Pulmonary Artery ◽  
Pulmonary Vasculature ◽  
Pulmonary Vascular Disease ◽  
Systolic Pulmonary Arterial Pressure ◽  
Pulmonary Arterial ◽  
Circulating Levels

Introduction: Hypertension and hyperperfusion of the pulmonary vascular bed in the setting of congenital cardiac malformations may lead to progressive pulmonary vascular disease. To improve the understanding of the basic mechanisms of this disease, there is a need for clinically relevant animal models which reflect the disease process. Material and Results: We randomly allocated 45 newborn pigs, at the age of 48 hrs, to groups in which there was either construction of a 3 mm central aorto-pulmonary shunt, undertaken in 9, or ligation of the left pulmonary artery, achieved in 13. Controls included sham operations in 13, or no operations in 10 pigs. Follow-up was continued for three months. The interventions were compatible with survival in most pigs. The shunts resulted in an acute 85% increase in systolic pulmonary arterial pressure, and a more than twofold increase in pulmonary blood flow. By three months of age, nearly all shunts had closed spontaneously, and haemodynamics were normal. Ligation of the left pulmonary artery resulted in a normal total pulmonary blood flow, despite only the right lung being perfused, and a 33% increase in systolic pulmonary arterial pressure. These haemodynamic changes were maintained throughout the period of study. In both groups, histomorphometry revealed markedly increased muscularity of the intra-acinar pulmonary arteries. Circulating levels of endothelin were normal in the shunted animals, and elevated in those with ligation of the left pulmonary artery. Conclusion: In neonatal porcine models of pulmonary vascular disease, created by construction of 3 mm central aorto-pulmonary shunts and ligation of one pulmonary artery, we observed histopathological changes of the pulmonary vasculature similar to early hypertensive pulmonary vascular disease in humans. Elevated circulating levels of endothelin were associated with abnormal haemodynamics rather than abnormal pathology. These findings could be valuable for future studies on the pathogenesis of hypertensive pulmonary vascular disease associated with congenital cardiac malformations.

Endothelin-1 vasoactive responses in lambs with pulmonary hypertension and increased pulmonary blood flow

1995 ◽  
Vol 269 (6) ◽  
pp. H1965-H1972 ◽  
Author(s):  
J. Wong ◽  
V. M. Reddy ◽  
K. Hendricks-Munoz ◽  
J. R. Liddicoat ◽  
R. Gerrets ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulmonary Hypertension ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Pulmonary Blood Flow ◽  
Heart Diseases ◽  
Main Pulmonary Artery ◽  
Similar Degree ◽  
Fetal Sheep ◽  
Endothelin 1

Increased concentrations of endothelin-1 (ET-1) are found in children with congenital heart diseases that produce increased pulmonary blood flow and pulmonary hypertension, but the role of ET-1 in the pathophysiology of pulmonary hypertension is unclear. Therefore, we investigated ET-1-induced vasoactive responses and ET-1 concentrations in an animal model of pulmonary hypertension and increased pulmonary blood flow. Vascular shunts were placed between the ascending aorta and main pulmonary artery in seven late-gestation fetal sheep. Four weeks after spontaneous delivery, ET-1 increased pulmonary vascular resistance by 29.7 +/- 34.4% (P < 0.05), the ETb-receptor agonist [Ala1,3,11,15]ET-1 (4AlaET-1) had no effect, and the ETa-receptor antagonist cyclo(D-Asp-L-Pro-D-Val-L-Leu-D-Trp) (BQ-123) decreased pulmonary vascular resistance by -16.0 +/- 5.6% (P < 0.05). In contrast, in six control lambs with a similar degree of pulmonary hypertension induced by U-46619, ET-1 and 4AlaET-1 decreased pulmonary vascular resistance by 24.8 +/- 17.6, and 20.0 +/- 13.8%, respectively (P < 0.05). In addition, systemic arterial concentrations of immunoreactive ET-1 were elevated in lambs with pulmonary hypertension (29.2 +/- 9.6 vs. 15.2 +/- 10.7 pg/ml, P < 0.05). Pulmonary hypertension and increased pulmonary blood flow alters the response of ET-1 from pulmonary vasodilation to vasoconstriction. These altered responses suggest a role for ET-1 and its receptors in the pathogenesis of pulmonary hypertension secondary to increased pulmonary blood flow.

scholarly journals Bidirectional Ductal Shunting and Preductal to Postductal Oxygenation Gradient in Persistent Pulmonary Hypertension of the Newborn

Children ◽  
2020 ◽  
Vol 7 (9) ◽  
pp. 137
Author(s):  
Amy Lesneski ◽  
Morgan Hardie ◽  
William Ferrier ◽  
Satyan Lakshminrusimha ◽  
Payam Vali
Keyword(s):  
Blood Flow ◽  
Pulmonary Hypertension ◽  
Pulmonary Blood Flow ◽  
Ductus Arteriosus ◽  
Arterial Oxygen Tension ◽  
Persistent Pulmonary Hypertension ◽  
Arterial Oxygen ◽  
Meconium Aspiration ◽  
Arterial Blood Gas ◽  
Arterial Blood

Background: The aim was to evaluate the relationship between the direction of the patent ductus arteriosus (PDA) shunt and the pre- and postductal gradient for arterial blood gas (ABG) parameters in a lamb model of meconium aspiration syndrome (MAS) with persistent pulmonary hypertension of the newborn (PPHN). Methods: PPHN was induced by intermittent umbilical cord occlusion and the aspiration of meconium through the tracheal tube. After delivery, 13 lambs were ventilated and simultaneous 129 pairs of pre- and postductal ABG were drawn (right carotid and umbilical artery, respectively) while recording the PDA and the carotid and pulmonary blood flow. Results: Meconium aspiration resulted in hypoxemia. The bidirectional ductal shunt had a lower postductal partial arterial oxygen tension ([PaO2] with lower PaO2/FiO2 ratio—97 ± 36 vs. 130 ± 65 mmHg) and left pulmonary flow (81 ± 52 vs. 133 ± 82 mL/kg/min). However, 56% of the samples with a bidirectional shunt had a pre- and postductal saturation gradient of < 3%. Conclusions: The presence of a bidirectional ductal shunt is associated with hypoxemia and low pulmonary blood flow. The absence of a pre- and postductal saturation difference is frequently observed with bidirectional right-to-left shunting through the PDA, and does not exclude a diagnosis of PPHN in this model.

Altered endothelium-dependent responses in lambs with pulmonary hypertension and increased pulmonary blood flow

1996 ◽  
Vol 271 (2) ◽  
pp. H562-H570 ◽  
Author(s):  
V. M. Reddy ◽  
J. Wong ◽  
J. R. Liddicoat ◽  
M. Johengen ◽  
R. Chang ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulmonary Hypertension ◽  
Endothelial Function ◽  
Pulmonary Blood Flow ◽  
Main Pulmonary Artery ◽  
Plasma Concentrations ◽  
Phosphodiesterase Inhibitor ◽  
No Synthase ◽  
Late Gestation ◽  
Fetal Sheep

To investigate early endothelial function associated with increased pulmonary blood flow, vascular shunts were placed between the ascending aorta and main pulmonary artery in 18 late-gestation fetal sheep. Four weeks after delivery, the lambs were instrumented to measure vascular pressures and blood flows, and blood was collected to measure plasma concentrations of guanosine 3',5'-cyclic monophosphate [cGMP, the second messenger to nitric oxide (NO)-mediated vasodilation] and L-arginine (the precursor for NO synthesis). The responses to the endothelium-dependent vasodilators acetylcholine (ACh, 1.0 microgram/kg) and ATP (0.1 mg.kg-1.min-1), the endothelium-independent vasodilators M & B-22948 (a cGMP-specific phosphodiesterase inhibitor, 2.5 mg/kg) and inhaled NO (40 ppm), and N omega-nitro-L-arginine (an inhibitor of NO synthase, 5 mg/kg) were then compared with responses in 12 age-matched controls. Vasodilator responses in control lambs were determined during pulmonary hypertension induced by U-46619 (a thromboxane A2 mimic). Shunted lambs displayed a selective impairment of endothelium-dependent pulmonary vasodilation, an augmented pulmonary vasoconstricting response to NO synthase inhibition, increased plasma cGMP concentrations, and decreased L-arginine concentrations. Taken together, these data suggest that lambs with pulmonary hypertension and increased pulmonary blood flow have early aberrations in endothelial function, as manifested by increased basal NO activity, that cannot be further increased by agonist-induced endothelium-dependent vasodilators.

Functional adaptation and remodeling of pulmonary artery in flow-induced pulmonary hypertension

2005 ◽  
Vol 289 (6) ◽  
pp. H2334-H2341 ◽  
Author(s):  
Chen-Fuh Lam ◽  
Timothy E. Peterson ◽  
Anthony J. Croatt ◽  
Karl A. Nath ◽  
Zvonimir S. Katusic
Keyword(s):  
Blood Flow ◽  
Pulmonary Hypertension ◽  
Pulmonary Artery ◽  
Pulmonary Blood Flow ◽  
Morphological Changes ◽  
Isometric Force ◽  
Functional Adaptation ◽  
No Donor ◽  
Vasomotor Function ◽  
Cox 2

Patients with left-to-right shunt congenital heart disease may develop pulmonary hypertension. Perioperative mortality of these patients is high due to abnormal vasoreactivity of the pulmonary artery (PA). We studied the changes in the PA induced by high pulmonary blood flow in rats with aortocaval fistula. Eight weeks after surgery, morphological changes of the PA were studied and vasomotor function was assessed by isometric force recording. Expression of endothelial nitric oxide (NO) synthase (eNOS), VEGF, and cyclooxygenase-2 (COX-2) proteins and levels of cGMP in the PA were analyzed. Rats with high pulmonary blood flow developed pulmonary hypertension, medial thickening, and increasing of internal elastic lamina and basement membrane in the PA. When compared with sham-operated animals, rats with fistula had significantly increased contractions in the PA, whereas relaxations to acetylcholine and NO donor were reduced. Concentrations of cGMP were reduced in the PA of rats with pulmonary hypertension (18.4 ± 3.3 vs. 9.4 ± 1.7 pmol/mg protein; P = 0.04). The altered vasomotor function was normalized by treatment with indomethacin. The PA of rats with fistula expressed higher levels of eNOS, phosphorylated eNOS, and COX-2. Sustained high PA blood flow in rats causes pulmonary hypertension that is morphologically and functionally identical with patients with flow-induced pulmonary hypertension. Abnormal vasomotor function of the PA in these animals appears to be mediated by reduced availability and the biological effect of endogenous NO and the high production of vasoconstrictor prostanoids. Increased eNOS and phosphorylated eNOS are most likely the adaptive changes in response to an increase in PA pressure secondary to high blood flow.

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