The effect of postural changes (ortho- and antiorthostatic tests) and LBNP on coronary circulation was investigated in 11 healthy male test subjects. Volume blood flow velocity and pressure were measured and blood flowing from the heart was withdrawn using a Ganz catheter implanted into the coronary sinus. A thin Teflon catheter was implanted into the brachial artery. When the test subjects were transferred from the recumbent to the head-up position, their left ventricular oxygen consumption decreased by 3.2 ml/min (21%) and coronary blood flow by 23.8 ml/min (19%), while coronary vascular resistance increased by 32%. When the test subjects were transferred from the head-up to the head-down position (at -15 degrees), coronary oxygen consumption and blood flow increased by 5.5 (46%) and 45.3 (44%) ml/min, respectively, and coronary resistance decreased by 36%. In this situation the LBNP test (-30 mm Hg for 20 min) caused a reduction in oxygen consumption and coronary blood flow by 4.4 (25%) and 37.3 (25% 7 ml/min, respectively, and an increase in coronary resistance by 58%.
Download full-text PDF |
Source |
|---|
Publication Analysis
Top Keywords
Similar Publications
TIGIT-expression on natural killer cell subsets is an early indicator of alleviating liver inflammation following bulevirtide treatment in chronic hepatitis D.
Hepatology
January 2025
Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology, Hannover Medical School, Carl-Neuberg Str. 1, 30625 Hannover, Germany.
Background Aims: Bulevirtide (BLV) is a novel and the only approved treatment option for patients with chronic hepatitis D (CHD). BLV alleviates liver inflammation already early during treatment when only minor HDV RNA changes are observed. We hypothesized that BLV-treatment may influence immune cells in CHD patients and performed a high-resolution analysis of natural killer (NK) cells before and during BLV-therapy.
View Article and Find Full Text PDFParametric Search for Optimal Channel Shape for Swirling Blood Flow in the Heart and Main Vessels.
Dokl Biochem Biophys
January 2025
Bakulev National Medical Research Center for Cardiovascular Surgery, Moscow, Russia.
The study presents a numerical parametric investigation of flow structures in channels with a longitudinal-radial profile zR = Const and a spherical dome at the base. The goal of the study was to examine the flow structures in these channels depending on the exponent N of the profile and the height of the dome, to determine the conditions that provide optimal centripetal swirling flow, analogous to blood flow in the heart chambers and major vessels. The investigation was conducted using a comparative analysis of flow structures in channel configurations zR = Const, carried out in two stages.
View Article and Find Full Text PDFKey Structural Features of Microvascular Networks Leading to the Formation of Multiple Equilibria.
Bull Math Biol
January 2025
Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Woodstock Rd, Oxford, Oxfordshire, OX2 6GG, UK.
We analyse mathematical models of blood flow in two simple vascular networks in order to identify structural features that lead to the formation of multiple equilibria. Our models are based on existing rules for blood rheology and haematocrit splitting. By performing bifurcation analysis on these simple network flow models, we identify a link between the changing flow direction in key vessels and the existence of multiple equilibria.
View Article and Find Full Text PDFMicrofluidic vessel-on-chip platform for investigation of cellular defects in venous malformations and responses to various shear stress and flow conditions.
Lab Chip
January 2025
Oulu Center for Cell-Matrix Research, Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5000, FI-90014 Oulu, Finland.
A novel microfluidic platform was designed to study the cellular architecture of endothelial cells (ECs) in an environment replicating the 3D organization and flow of blood vessels. In particular, the platform was constructed to investigate EC defects in slow-flow venous malformations (VMs) under varying shear stress and flow conditions. The platform featured a standard microtiter plate footprint containing 32 microfluidic units capable of replicating wall shear stress (WSS) in normal veins and enabling precise control of shear stress and flow directionality without the need for complex pumping systems.
View Article and Find Full Text PDFImaging of the Placenta.
Clin Obstet Gynecol
March 2025
Department of Obstetrics, Gynecology and Reproductive Sciences, School of Medicine, University of Maryland, College Park, Maryland.
Placental imaging is crucial in prenatal care, offering insights into both normal and abnormal pregnancies. Traditional methods like grayscale ultrasound and magnetic resonance imaging evaluate placental anatomy, whereas Doppler ultrasound is used for functional assessment. Recent advancements include functional magnetic resonance imaging and advanced Doppler software for demonstrating placental density and visualizing spiral arteries.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!